They Wasted a Perfectly Good Plot/Film

""You'd think a premise as simple as "Vampire chick kills Nazis and grinds against lesbians" would be hard to screw up. But you don't know Uwe.""

- The Spoony One on the film version of |BloodRayne

Examples of in  include:

Films - Animation

 * Madagascar could have been the perfect film to satirize and cure the one-sided "Free Willy" syndrome affecting movie goers up to that point - that is, belief that captivity is evil and the natural lives of animals are utopian. It shows a peaceful and friendly lion from a zoo released into the wild accidentally, and the film even goes through the motions of being yet another "Free Willy." Soon, he begins to revert to bloodthirsty Darwinian survival behaviors, and the film assumes a darkly comical aura of showing nature's more savage side to the ironic tune of "What a Wonderful World" in line with the motif. And where do they go with all that potential?
 * The Tim Burton-produced movie 9 looked like it was building up to an interesting end as
 * Batman Beyond: The Return of the Joker, the direct-to-DVD film that capped off the Batman Beyond series, made it look like Though one has to wonder if the stated potential idea would have been even possible to get past the censors.....
 * Titan A.E. could have saved Don Bluth's career and delivered a blow to the Animation Age Ghetto stereotype. The plot idea was epic enough. Get ready for high flying cosmic adventure, right? Not if Fox has anything to say about it! The movie was rushed and underfunded, and an Ass Pull of a reveal didn't help either.
 * It had a creepy-ass villain, great voice actors, great animation, Spielberg, dinosaurs... How could We're Back! A Dinosaur's Story suck so hard?
 * Shrek 4: In a Bad Future Shrek was never born and never met his true love Fiona. It would have been interesting if someone else was Fiona's true love and seeing Shrek deal with that, but Fiona loves Shrek regardless.

Films - Live Action

 * Alien vs. Predator falls into this category. Fans were expecting a decently-budgeted movie that had Colonial Space Marines fighting with Xenomorphs, and Yautjas in the far future, but what they got was a small budget PG-13 film set on present-day Earth.
 * Let's not forget Aliens Vs. Predator: Requiem. While the first film had let people down, the ending of that movie promised something bigger and better (the Predalien hybrid). Coupled with early teasers and posters showing both aliens and predators on Earth (and released during the Christmas season), there were high hopes that this would be the true battle of the species everyone was waiting for. What a shame, then, that the film is set in the present day (not the future, which meant there was no futuristic technology or Marine presence) and that the Predator's and Gunnison residents' stories are almost completely separate. Not to mention that more than half of the film is devoted to a romance subplot between a pizza delivery boy, a female high school student and her Jerk Jock boyfriend that would have fit better on a primetime TV series.
 * Similarly, Alien 3. The first film had a lone xenomorph wipe out most of the crew of a starship. The sequel upped the stakes by having most of an entire Marine squadron (and an entire colony) wiped out over the course of the film. With the "Earth" teaser that was released in 1991 (and following Sigourney Weaver's Oscar-nominated performance), it appeared to be common sense that the third film would be the biggest yet, having an all-out war between Marines and xenomorphs on Earth. Instead, the final product was a small, more intimate return to the first film, with a cast of loathsome inmates and a main character who had essentially resigned herself to suicide (which, if not necessarily bad in its own right, was a tonal step back from the white-knuckle thrills and positive character development of the previous film). Considering what several other writers had originally planned before FOX decided on a prison setting and the death of the main character (including a script by William Gibson set aboard a space station above Earth, as well as an early treatment of the aforementioned AVP film that would have had a massive battle royale between Marines, Predators and Xenomorphs), Alien 3 felt like a step backwards.
 * Awake. Until the halfway point it seemed to have a strong possibility of having a decent ending where the character's . The film can serve as a tutorial on how NOT to make a suspense movie.
 * Billy the Kid vs. Dracula. Seriously, that's one of the best concepts for a movie ever, but the script takes almost everything interesting out of it. Billy the Kid's no longer an outlaw, Dracula's just a generic European vampire in a top hat, the acting's wooden, and the special effects are the cheapest of the cheap. The crapitude reaches maximum levels during the final battle, when, after Dracula proves himself Immune to Bullets, Billy the Kid wins by throwing his frickin' gun and knocking the Count out! John Carradine, whose career seemed to be built on highs and lows, chose this movie as the worst one he was ever in, which is definitely saying something.
 * Considering John Carradine was in Red Zone Cuba (aka Night Train To Mundo Fine, aka one of the worst films ever given the Mystery Science Theater 3000 treatment, that is indeed saying something.
 * Blade Trinity: in the first film, Blade has to fight the physical manifestation of a vampire god; the souls of 12 vampire elders infused into one vampire, making him much stronger and faster than Blade, not to mention a Healing Factor. In the sequel, the main enemy is a genetically engineered strain of vampire with almost none of the traditional weaknesses, that in the end . In this film, Blade is pitted against Dracula; the first vampire, who has NONE of the weaknesses exibited by his species, even sunlight. Sound good? Such a shame the dialogue was better suited for a high school film, Blade is all but replaced by normal humans who had their own subplots take up much of the screen time, and the final battle with "Drake" was the slowest and least intense final battle of the trilogy.
 * Blade II is usually considered the best movie in the series but it too had a wasted plot. The Blood Pack were assassins trained to hunt and kill Blade. A movie depicting Blade going up against his own set of hunters would've been interesting enough on its own. Instead, the Blood Pack help him take on the Reavers which could've been a good setup for a third film after the second featured Blade against the team.
 * Charlie's Angels 2. Three smoking hot babes that kick butt. A mysterious mentor. The other Bosley. An evil Angel. John Cleese. So much potential for awesome, traded so that the Angels could do some utterly ludicrous nonsense no one could ever possibly survive and all John Cleese did was run around looking shocked. Wasted a plot and actors.
 * The writers of Deja Vu certainly felt this happened when director Tony Scott concentrated too much on the action aspect of the movie. To the extent that one of the writers refused to even watch the film when it came out after he saw how the filming was going.
 * Stephen King's Dream Catcher. The problem here is presumably that they attempted to do too much. Evil alien parasites  - definitely scary. A military officer   - potentially great. A group of kids who can use   to do good magic - offensive, but not much so than many things that come out of Hollywood these days. All of those things at once, adding in the big reveal that  ? An incoherent, cliched mess.
 * In Drillbit Taylor, the Jerkass step-father of one of the kids told his son a story about how he used to bully this one kid in high school. You'd expect this to lead up to something, with Drillbit turning out to be that kid and getting revenge, but sadly that was not meant to be.
 * Edison had a plot point about the corrupt police department funding the DA's political campaign via a money-laundering scheme. It gets mentioned exactly once in the entire film. Instead of that plot, we get Justin Timberlake attempting to act opposite Morgan Freeman.
 * Event Horizon. A ship uses a new technology to travel at faster-than-light speeds. However, the process drives its crew insane and imbues the ship with an otherworldy presence. This film's new take on a classic sci-fi technology could have made for a powerful psychological thriller, but instead it turned into another generic monster movie.
 * The Final Cut. The story is set in the future; where implanted microchips can record all moments of an individual's life. Sounds good. Until; 'The chips are removed upon death so the images can be edited into something of a highlight reel for loved ones who want to remember the deceased.' Complications occur, but such a waste when so many interesting plots could have arose from the starting idea.
 * Finding Forrester. A Black inner city teenager befriends a famous elderly reclusive author. The concept sets the story up for rich drama, complex characters, and compelling developments. There are a million things the story could have explored. It didn't. Neither of the characters grew, or learned anything from each other, or changed in any way, or even had any meaningful conversations. Regarding the necessary theme of racism, the only thing the story did was show us that some people will assume Black people are dumb and those people are bad. Thanks a lot. People interested in that kind of film already knew that, thank you very much, and would have liked to see the more complex aspects of racism addressed at least a little bit.
 * The Forbidden Kingdom was marketed as a story in which two rivals had to fight together to overcome a common enemy. These rivals just happened to be played by Jackie Chan and Jet Li, together on the same screen for the first time combined with over the top special effects. And then they introduced Jason's character and made the entire movie about him, with Jackie and Jet as supporting characters.
 * It really would have been fine if the kid had just been Chinese. The random Aliens Speaking English thing would've still worked too - its depressingly common for Chinese-Americans (or other immigrants) to not speak their anscestral tongue. Having a white kid be the hero just threw Unfortunate Implications into an otherwise fine movie.
 * Gamer: A future so terrible that people are willing to literally rent out their free will to survive? A movie based on that premise alone has a lot of gold to mine, but instead it focuses on a The Running Man ripoff that is shot so poorly the audience has no idea what's happening.
 * Ginormous waste of a cast as well. Went out of their way to hire all the biggest players currently (as of '07-'10) as well as all the biggest players of movie channel series like Dexter. And somehow at the end of the day, the script and writing made it feel like Ahrnahd was a better actor than all of them.
 * Hancock. Oy, Hancock. The title character is a bitter, caustic, alcoholic superhero whose good works are outpaced by his collateral damage and doucheness. A man who barely seems to care about helping people, Hancock is held in contempt by his city as a result of the mayhem he's caused. After saving the life of a PR specialist named Ray, the grateful specialist offers to help clean up Hancock's image and behavior, and to help him become the kind of hero he is capable of being. This plot is derailed by the revelation that  shares Hancock's powers and knows his shrouded origins.  then completely fails to adequately explain those origins, saying only that they're connected, both really old, that they've been known as gods, angels, and superheroes, and that all others of their kind have died off. We never get another glimpse of Hancock's personal redemption.  Would it have killed the writers to just boost someone to Hancock's level for the climactic fight? This could have been a great movie if it had just stuck to what it promised in the first part.
 * One reviewer described Hancock as the best first half of a superhero movie he'd ever seen followed by the worst second half of any movie he'd ever seen.
 * Hancock is the story of a black superhero who is immortal and who has been public public for the past century. There would be massive implications if a character like that had been around during the civil rights movement. Did Martin Luther King or Malcolm X try to talk to him? Did he ever get angry to the point of hunting down the Klan? And yet, we hear nothing about it.
 * Hellboy 2 wasted a potential plot point set up in the first film. Most of the first film was centered around Professor Broom grooming John Myers to be his replacement as Hellboy's caretaker. The second film could have shown how much John matured in the time between films, and how his duty as the new caretaker of Hellboy would have evolved. Instead, his character is Put on a Bus since Hellboy somehow managed to get him literally Reassigned to Antarctica.
 * Pursuit of Happyness is a Will Smith movie that markets itself as an American Dream story where one man overcomes the odds through sheer will and determination to go from being homeless to being a Wall Street exec by receiving high marks on a test. Unfortunately, we never see him actually do anything to prepare for the test, because every time he tries, something bad happens to distract him. Instead, the climax has him walking into the exam room, walking out some time later, and then being told that he has the job a few days later. Imagine watching "The Mighty Ducks" where you never see the team training, all the games take place off screen, but we're still supposed to cheer when they bring home the trophy.
 * Actually, it's stated earlier that you can score perfectly on the test, but still lose. Since the movie mentions prior that that winning depends on the amount of sales, and the movie is very careful to demonstrate how Smith's character made those sales, it doesn't seem like a very good example.
 * I Know Who Killed Me has a girl kidnapped, and then show up a few days later horribly maimed, believing she was someone else (one of the characters in her stories, to be specific). There are about a billion ways that could have gone right - but they chose one of the few very wrong ways to do it.  Good so far.
 * Inkheart. There are these people called "Readers" who have the power to summon characters and objects from storybooks into our world. There are so many awesome and creative places to take that premise... and you choose instead to make a generic movie with a by-the-numbers plot that doesn't seem to go anywhere, forgettable bland characters, a laughable villain, disappointingly little of the book-summoning power, and an ending stuffed with so much cheese that my arteries are in desperate need of unclogging!
 * Jesus Christ Vampire Hunter. One would have hoped the eponymous protagonist would... resemble (typical portrayals of) Jesus in the slightest.
 * Knowing. A fifty-year-old sheet of numbers, written by a strange schoolgirl with precognitive powers, is found in a time capsule and predicts every major disaster from the past fifty years after being decoded? And there are three left that are due to happen in the next week? Sweet, sign me up. The protagonist has spiritual issues and gets bamboozled by enigmatic black-suited telepaths? Well, not quite what I expected, but alright, we can go somewhere with this. The whole story turns out to be ? Uh... wait. Is it too late to go back to that first part and try again?
 * Worse, it's not convoluted so much as a whole bunch of things look like they're going to be important but aren't, as the aliens calmly execute "plan: take the kids." The numbers, the predictions, the frantic chases across town... all turned out to have no bearing on the plot, and not even in a "well-executed Shaggy Dog Story" sort of way.
 * It's more of a case of "They wasted a perfectly good documentary", but it seems a shame that Steve McQueen's 1970 Le Mans film had to be a half-baked fictional narrative with barely any dialogue. Half the film is the real race anyway, and posterity would've loved to have Steve McQueen interviewing the drivers of the time. Executive Meddling would've likely scuppered such an idea, since it would've involved Steve taking a back seat.
 * Licence to Kill: A James Bond film to break from the 007 tradition and turn our hero into a rogue agent had potential - even if "hey, my buddy's been hurt and his wife's been killed, so I want Revenge" is hardly original - but it was marred by poor dialogue, unimaginative gadgets, mediocre acting (except that of Timothy Dalton and Robert Davi), and lackluster direction, putting the brakes on the 007 film series for six years.
 * A View to a Kill had an interesting dilemma staring the filmmakers in the face: Roger Moore was clearly past his prime as Bond, and was visibly straining to perform the stunts required throughout the film. Several options were clearly apparent: they could have made the film a nice send-off for Moore (and had the character either retire or transfer his mantle to a new agent - The Living Daylights, which had Bond on a training mission, was made right after this, and would have made a good segway) or they could have done anything else than what ended up onscreen. A lame retread of Goldfinger (with an oil baron replacing a gold magnate), complete with 007 sleeping with a woman young enough to be his granddaughter, stunt sequences that are either shoddy or unimaginative, and a general sense that everyone involved was just in it for the money.
 * Die Another Day (which was made primarily to commemorate the franchise's 40th anniversary) also falls into this, as it had several disparate plots that could have been cool on their own...but failed miserably. On Bond's "last mission", he is betrayed by his superiors and captured by the Korean government. The backdrop is an escalating conflict between North and South Korea that forces U.S. intervention (something that still resonates in the 2010's). Bond is looking for revenge against a thought-dead Korean general, who is using a cover story to take power in the region. In the right hands, the film could have been a cool throwback to the 80's Bond films. Instead, director Lee Tamahori took the material way over the top by including an invisible car, a Kill Sat laser that is slow enough that a speeding car can outrace it, a Korean man using gene therapy to become a white British man, another Korean man with diamonds stuck on his face and absurd action sequences. The end result killed the franchise for four years and eventually resulted in its reboot with Casino Royale.
 * Might as well throw another one on the pile: how about Diamonds Are Forever? After the unfortunate events in the previous film, it would be great to see James Bond, played once again by George Lazenby, on a personal mission to kill Blofeld and avenge his wife's death. Sadly, Lazenby left the role due to many reasons, and Connery was brought back. It could still work, right? Nope. Too bad that after the Cold Open he seems to forget all about his dead wife, the rest of the movie is filled to the brim with cheese, Sean Connery's just there for one last paycheck and we get no real resolution to the rivalry with Blofeld (unless you count the unceremonious one in For Your Eyes Only).
 * It should be noted that all three of these are the last for their Bond actors, meaning they're not just wasted plots but shoddy send offs to their eras as well.
 * Life Size: Our first introduction to a pre-drugs Lindsay Lohan? Taking off a (American) football helmet to establish that she's on the school football team. Actual plot? A doll she's received as a gift turning into a pre-ANTM Tyra Banks. How long it takes to get back to the football? The better part of an hour.
 * Manos: The Hands of Fate, one of the worst movies in history, has a fundamentally sound plot: a young family driving across country stops at an out-of-the-way motel, staffed by a possibly non-human caretaker, which is the home of a strange and terrible cult focused on the mysterious Master. The cultists are out to induct the family by any means. The actors are reasonably well-cast and the script, though nothing special, is at least fairly decent. The location chosen for the shooting was suitably atmospheric, the Master's many "brides" suitably beautiful and Torgo's voice suitably peculiar. Somehow, the entire cast and crew still blew it completely.
 * The Matrix: Revolutions. They could have done something completely awesome with this film. At the very end of Reloaded we discover that Neo has powers OUTSIDE the Matrix. And yet, instead of pursuing this to its logical and mindbendingly depressing conclusion that Neo, Trinity, Morpheus and everyone in Zion are STILL INSIDE THE MATRIX...
 * Smith ended up taking over the Matrix, which could have led to a few scenes of Smith taking out armies, possessing people while they give newscasts, and generally taking over the world.
 * The fight scene between uber-powerful Neo and Smith was also wasted. They fly at each other fist-first a lot instead of doing something cool like hurling mountains and lightning.
 * To sum up just how badly this movie wasted potential plots, things implied by the second movie include: a multi-level Matrix that Zion would be part of, the Merovingian being a former "One" who chose to continue the Matrix rather than destroy it (which implies moral angst for Neo as he decides what to do), the possibility that Neo's choice to save Trinity will kill everything in the Matrix, the fact that, Agents possibly having to team up with freedom fighters to defeat Smith, the aforementioned ghosts, werewolves, aliens, etc., and so much more. The fact that the final movie has NONE OF THAT is mind-boggling.
 * The Matrix: Reloaded also fits here. The Merovingians' viruses are supposed to be the ghosts, vampires, and monsters of legend. We only get a few glimpses of werewolves once and the ghost twins. The rest are indistinct from any other Matrix character. We could've had some insane Neo vs. werewolves subplot and broadened the world of the Matrix. Instead, we got more of the same. That's to say nothing of characters like the Architect who pop up and leave abruptly.
 * Some more scenes of Smith in a human body would have been interesting too, since its a reversal of the normal humans-in-machines of the movie and and show how he handles actually being free.
 * Men in Black II. Jay needs to bring a mind-wiped Kay back because the MIB has been compromised, and Kay needs to look back into his own memory to save the world? Great! The roles are now reversed from the first film - Jay is the hard-bitten vet and Kay the over-his-head rookie. They try to use the De-Neuralizer to bring Kay's memory back, but it doesn't work and Kay leaves, angry that this is all some crazy hoax. But then it suddenly DOES work, and instead of having Kay come along for the ride because he's a good guy, he just puts on his shades and goes back to kicking alien butt. So all character development is instantly erased. Way to go.
 * One Night with the King. The story of Esther: a beautiful woman who becomes the queen of all Persia risks execution in order to save the lives of her own people. Add some gorgeous costumes, beautiful cinematography and high-profile actors like Peter O'Toole and John Rhys-Davies and you've got a pretty good movie, right? WRONG. Top it all off with a horrible script, unnecessary subplots, not-funny jokes, weird editing and all of the actors trying to out-ham each other, and they heavily outweigh any redeeming factors the film originally had.
 * Percy Jackson and The Olympians: Annabeth is the daughter of Athena, and proclaims her the Goddess of Widsom and "Battle Strategy." Okay, traditionally she's described as the goddess of widsom and war, but then it would be hard to justify Percy defeating her in single combat. That's fine. Besides, that was a perfect set up to make her a Non Action Girl while totally avoiding Chickification. Her rather vapid stare could easily have been passed off as the unseeing gaze of focused genius, and she could have acted rather like the Hermione of the group, focused on the overall strategic goals and planning the plot stages of the quest. Percy would shine as the brawn of the outfit, with Annabeth acting as the brains. If she had been allowed to plan their assault on Hades, perhaps it wouldn't have been quite so haphazard. The exposition early in the movie set things up so perfectly for Annabeth to step into the leadership role, that it almost seemed like Obfuscating Stupidity when she repeatedly refused to act. What a waste. In the books, Annabeth is more clearly the brains of the operation.
 * Philadelphia. Here we have a sick man who's obviously in denial of the seriousness of his condition, even while he seems to have gotten more than used to soaking attention form everything else, to the point of his boyfriend being obsessed with taking care of him, . In short, we have a good illustration of how AIDS consumes even the lives of those around its victim passing under the guise of a supporting family while the trial takes center stage.
 * Kindly mind the Gay Aesop.
 * Agreeing with the above. The point of the movie wasn't so much the protagonist's struggle with AIDS but his battle to set things right with the homophobic law firm he was fired from, with the help of a lawyer who himself was a little homophobic before he really got to know Tom Hanks's character. In the early 1990s, there remained at least memories of the time period (the 1980s) when people with AIDS were routinely shunned by whole communities (cf. Ryan White) and AIDS was snidely viewed as "the gay curse".
 * Besides, he didn't necessarily cheat on him; he might have had it before they met, as it can take many years to show itself. (Now, how his boyfriend didn't get it from him I'm not sure, but...)
 * He did cheat, though. He said that he'd had sex with the random guy in the theater while he was with his partner, knowing that he could have infected said partner.
 * AIDS isn't universally infectious in all directions; his boyfriend could be a top, or maybe they only use non-penetrative sex. Or, my god, they could have taken things seriously and used protection.
 * Push was pretty well thought out: some people are gifted with psychic powers, and a government group called Division wants to capture all of them to use them as weapons. It was mostly supposed to be an action movie, but there were only fifteen minutes of actual action throughout the movie (and that's being generous), making the whole movie rather tedious.
 * Robin Hood (2010 film), while pretty good as is, is a MAJOR difference from what the original idea was. They were going to make a film called "Nottingham", where Robin Hood is the villain and it's about the sheriff trying to figure out who he could be and the motivation, giving the other side of the story. The studio scrapped the script, claiming that audiences would never want to see this version.
 * The studio actually liked the story they bought just fine, the problem was that they hired Russell Crowe for the main role, who in turn demanded Ridley Scott as director, and Scott accepted because he had always wanted to make a movie about archery... which the original script considerably lacked. So he started demanding rewrites in order to put more archery into the story - at some point even introducing a twist where Robin and the Sheriff were the same person - before settling in a Robin hero origin story that wasn't very different from the other 100 Robin Hood movies filmed, and that ended being panned by critics for its unoriginal and weak script.
 * Reign of Fire is a movie where thousands of dragons take over modern-day Europe. However, they seem to have been convinced that actually watching thousands of dragons taking over modern-day Europe would have been too awesome for their movie, so we got newspaper clippings instead. Thus the most potentially-awesome element of the movie was left out entirely, and audiences left theaters everywhere, wondering how they could have messed up on something that basic.
 * The Strangers had the Nightmare Fuel plot about Home Invasion by total strangers Just For the Evulz utterly ruined by the characters being Too Dumb to Live Over 9000.
 * The adaptation of Clive Cussler's Sahara threw out the rather interesting  subplot for little good reason.
 * Saw VI tried to make a point about the horrible health insurance system... but blew it by having the main protagonist choose only female survivors and having them be the only ones with families that would miss them. The only guy who mentions his family does this just to say he's rich. And one character (Josh) is betrayed for Shelby. Apparently, the only people who matter are female. Yet, he's in these traps because he refused Jigsaw the insurance, and Jigsaw was a guy, and at the end,  This is either Fridge Brilliance or just plain bad writing.
 * Saw III has this even worse. Several years before the movie, a man has his son taken from him by a drunk driver. The driver gets off with only a minor sentence (a few months) and the father (Jeff) spends the entire intervening period mourning his son while completely ignoring his, still living, wife and child. So far, so good. Jigsaw decides that Jeff has been dwelling on this far too long and needs to forgive the people involved and move on with his life. It's a Saw film, so of course Jigsaw should be involved, so that's also fine. Sadly, the rest of the film is gore, gore, and more gore as the people that Jeff holds responsible are killed off in progressively awful ways, and you never get the impression that Jeff is emotionally affected by any of it. What could have been a horrific, but ultimately satisfying, journey of redemption is instead just a giant, pointless, bloodbath in which no one grows and nothing is learned.  I suppose that was the point (Jeff is irredeemable), but it's still a huge let down for such a promising concept.
 * Not affected? He  because he was in shock. The main point of the movie, though, is that not everybody learns their lesson (Jeff's was to forget about his desires of revenge, Amanda's was that everyone deserves a chance)
 * However, this was cited by Jigsaw himself . The traps were designed to be immune to disarming, and not by Jigsaw's doing.
 * He meant the first two traps in the movie, not the ones in Jeff's test.
 * Skyline. After 90 minutes of suffering through one of the dullest, most derivative alien invasions ever depicted on film, the main character and his pregnant girlfriend are finally abducted. Finally! Let's get out of...oh wait, there's more? Could it be...YES! They took his brain! Well, at least we get a happy en...wait, why is the brain glowing red? Why is this big alien robot acting weirdly? HOLY CRAP !!! Okay, so they're kind of ripping off District 9, but at this point, I'll take anything...wait, why are the credits showing up? FFFFFFFFUUUUUUUUU-
 * Star Trek: First Contact had an initial teaser trailer, made so early in production that it used stock shots from earlier movies as filler, made no mention of either the Borg Queen or Time Travel, and instead implied an all-out assault by the Borg Collective on the Federation. While First Contact is a highly regarded movie as it stands, that unused premise (along with the first twenty minutes of the film that also head in that direction before the story detours) would've been even more incredible.
 * It's worth noting that the original script draft HAD an all-out invasion by the Borg and a cameo appearance of "transphasic torpedoes" years before they appeared in Voyager. It was changed because it effectively de-clawed the Borg and prevented them from being a credible enemy in the movie.
 * Also, as Plinkett pointed out in his review of First Contact, the Defiant was meant to be an anti-Borg vessel, but showed up at the start of the film with only Worf on board. How much more awesome would the film have been if it had incorporated the entire Deep Space Nine cast into the movie as well- especially as the tension there would have been between Picard and Sisko once the issue of the Borg is raised between them again.
 * In all fairness to Paramount, Deep Space Nine was still filming and they had a hell of a time just getting Michael Dorn (Worf) for the film. Getting all or most of the regulars would've been impossible.
 * Also pointed out by Mr. Plinkett, Star Trek Generations features only half the original crew ("Whoever was lame enough to show up showed up."), Kirk's ultimate role is to replace Guinan as a distraction for Malcom McDowell, and Data's subplot is completely irrelevant.
 * Star Trek: Insurrection: As explained in Michael Pillar's unreleased book Fade In: The Making of Star Trek: Insurrection, the original plot was "Star Trek goes Apocalypse Now". Picard has to go apprehend a turncoat Federation lieutenant he served with in his Academy days, and ends up siding with the aforementioned lieutenant when Starfleet decides to invade the planet he's on. Then, Picard ends up on trial at the end and resigns his Captain's commission to go lone-wolf against his former employers. Sure, the plot was wild as hell, but you can't deny that it would have taken the franchise down a very interesting path (as it was intended to dovetail with what was happening over on Star Trek: Deep Space Nine, marking the franchise's shift into Darker and Edgier territory). Patrick Stewart loved the concept; Brent Spiner pushed for more screentime for Data. The final film turned out to be a feature length TNG episode concerning a "fountain of youth" and a weak moral conflict that's more or less resolved by the end of the film.
 * Star Trek: Nemesis: All the elements were there for a truly great film. The Romulans reclaiming their dominance after years of being in the background (they almost were the Big Bad of Star Trek III the Search For Spock). Picard's evil clone. A return to the "getting older and moving on" plot thread from Star Trek II the Wrath of Khan. Instead, what we got were half-baked plot threads cribbed from prior episodes of Next Generation, illogical chase sequences, a half-assed scenery-chewing villain and the pointless death of a main cast member. There's a reason why this killed the franchise until the 2009 film.
 * Brent Spiner wanted Data to be killed off because he thought he was getting too old for the part, but if the movie still leaves open the possibility of B4 taking Data's place after inheriting his memories, why didn't they cast a younger actor as B4 and have Patrick Stewart play a dual role as Picard and Shinzon?
 * When people heard Firefly was getting its own movie Serenity, everyone was looking forward to having the loose ends from the series tied up. Finally we'll learn Books backstory, finally we'll get a showdown with the Hands of Blue, those badass government types who can cause haemorrhages with sound. Instead of the Hands of Blue who were unceremoniously dropped, we get the (admittedly equally badass) Operative; and as for Book's backstory,  We had to wait for a comic book follow-up for both the Hands and Book's history.
 * Sunshine features scientists thinking and acting like actual scientists as they ride a city-sized bomb toward the dying sun in order to set off a chain reaction that might save Earth. The ship is beautifully designed and rotates for artificial gravity. The EVA suits are gold-lined and uniquely shaped for entirely logical reasons. Early plot points channel The Cold Equations. Characters act against cliche almost as a rule, and there's no standard-issue space marine a-hole hanging around to create useless conflict. The first two-thirds of the movie are some of the best science fiction ever filmed... and then the serial killer comes on board. Screw your nuanced character development, this script is now Jason X!
 * Superman IV: The Quest For Peace: Superman vows to rid the world of nuclear warheads, while his arch foe Lex Luthor decides to capitalize on this turn of events, creating a creature of incredible power unlike anything Superman has ever faced (in the movies anyway) while the Daily Planet is being bought out by a heartless tycoon and his jaded daughter - played by no less than Muriel Hemingway - who develops a crush on the nerdy Clark Kent. In the end, Superman realizes that even he cannot force peace upon the world. A tad politically preachy, perhaps, but it had the makings of being the greatest Superman movie of them all. Unfortunately...they didn't finish it. The massive plot holes and terrible special effects were the result of Cannon Pictures yanking the project away from the director, trimming a half-hour of important scenes so they could be used in a sequel (!?!) and putting much of the money given to them by Warner Brothers (distributors of the film and owners of the Superman character) into other projects.
 * You know how early moon missions would lose radio contact with Earth when the astronauts passed onto the dark side of the moon? That was just a lie to cover up what the astronauts were really doing: investigating a crashed alien starship. Awesome! That casts the US/USSR space race in a whole new light! Is this an alternate history piece exploring Cold War conspiracies and mixing in an extraterrestrial element? Nope, it's Transformers: Dark of the Moon.
 * The Trigger Effect was always one of these for me. Great premise - the power goes out, and stays out. No one knows why. Would have been a great study of the veneer of civilization slowly melting away (and does have a two or three good scenes) but then decays into a love triangle. Ugh. Primo material for a Fincher remake IMHO.
 * The entire Twilight Saga could count as this. You have armies of vampires and werewolves going at it, psychic powered vampires fighting other psychic powered vampires fighting werewolves, etc. And what is the focus? A love story surrounding a girl with the personality of a doorstop.
 * And the reverse could also be said. You have a gripping tale of romance about a girl and a boy who feels out of water, the boy isn't human and some of his family doesn't approve, the girl's blood is a vampire magnet and she's not sure whether she'll survive or not if she follows her heart. And instead of that, they shortchange the whole thing and replace it with blander dialogue in order to facilitate more vampire fights because people are under the impression that this is a vampire movie not a romance movie.
 * All in all, you could probably say that Twilight was two potentially good stories very badly mixed together.
 * The Village: This movie could have been really great. A late 19th century rural, AMERICAN village lives in uneasy coexistence with strange, humanoid monsters in the forest that surrounds their community? And these monsters are starting to become aggressive and the heroes have to find out why? There was just so MUCH there to make a good story. But no, we had to get  How do you screw something that good up?
 * Arguably it's not such a bad plot in the Internet Age, a whole village staying completely off the grid. The trick is making it believable.
 * The Warriors could be accused of this. It could have consisted entirely of a gang fighting their way through distinctive gangs one-by-one on their way to get home. Instead, this premise was dropped about halfway through, we get a tacked on love story, and there are only two big fights in the movie; the rest either have the Warriors run away or are quickly won.
 * Another point that the movie touched upon, but discarded early on is Cyrus' plans to unite all of New York's gangs into one unit. What tensions could have arisen from that? How would the police force handle it? What would ultimately happen to the city? Unfortunately, we'll never know the answers; fortunately, what comes after Cyrus' death is still a satisfying experience.
 * The Tim Allen film Zoom: sounds good on paper. A retired and bitter powerless Superhero must hastily teach teen mutants to fight his insane brother who's been stranded in another dimension? Great! The execution, however, was a mess. It looked like the filmmakers had seen other movies, and were aware of the existence of certain tropes and cliches, but had no idea why they worked or what context they worked in, and randomly tacked unrelated scenes together until they ran out of film. Using their rough draft script, no less. It didn't help that the "superhero school" plot had already been used a year earlier (and far more effectively) in Sky High, leaving many potential viewers to dismiss Zoom out-of-hand as a cheap rip-off.
 * Letters to Juliet concerns what happens when magazine writer Amanda Seyfried discovers that lovelorn women leave letters to Juliet of "Romeo and" fame in Verona, and is drawn to one in particular sent by Vanessa Redgrave. Now the movie could have been all about the writer of that particular letter, or focus on several different women, or even be about the women who write the replies to the letters... any of those would have been more interesting, and more romantic, than the decision to combine a tourist trip around Italy with a clunking, unamusing, and totally implausible romance between Seyfried and Redgrave's grandson (why she or anyone would fall in love with such a charmless, snooty prick is a mystery ).
 * Invoked deliberately in The Other Guys. The Rock and Samuel L. Jackson play badass cops who accomplish all sorts of crazy feats and daring rescues while stopping bad guys and trading cliched quips. The camaraderie between the two men seems like it would be good enough to carry an entire film, but the duo inexplicably decide to jump off a building (while chasing suspects) twenty minutes into the film, resulting in their (hilarious) deaths and a switch to the two cops played by Will Ferrell and Mark Wahlberg.
 * On the other hand; the trailers implied that either Ferrell would be some kind of supercop like Johnson and Jackson whose undercover, or that Johnson and Jackson would be the rival cops for Wahlberg and Ferrell to take down, showing the Jerk Sues up. Either would have made a more together movie, especially since they went WITH the rival cop idea but with less interesting actors who couldn't play up the roles as well as Johnson and Jackson.
 * The Descent started out as a movie based on the Primal Fear associated with being trapped in a cave. Halfway through, it turns out that there are monsters living in the cave, prompting a completely unnecessary Genre Shift to Slasher Movie.
 * Matter of opinion. The movie is still regarded as one of the best horror films ever made and the ending along made those speculate on the possibility that the person who survived the incident went crazy and killed her friends or if something was actually in the cave.
 * Bedazzled (2000) A romantic comedy where a guy makes a Deal with the Devil to try and get the girl-The Devil here is a super hot chick by the way...who wanted to see Elliot, the Dogged Nice Guy, ditch the unpleasable girl next door in favor of the Devil at the end? Come on, she's nicer to him, keeps "helping him" and she at least cares about him... Hey, it's not her fault if he doesn't word his wishes properly. Instead the film ends disappointingly with an Anvilicious Author Tract and Broken Aesop about how you shouldn't change how This Loser Is You and Elliot ends up with some bland Replacement Love Interest.
 * Son of the Mask: A boy with Mask powers, a dog that wears the Mask, and the maker of the Mask; all RealityWarpers and all mischievous. This had the making of a wild Crazy Awesome comedy; one scene even had the first and third play Super Twister ending with Loki planning to be a Big Brother Mentor, but only at the end. The potential here is just not expolited.
 * The movie Hot Rod has an interesting concept (wannabe daredevil decides to raise money to help his father get an organ transplant and win his love) and a decent supporting cast (Isla Fisher, Ian MacShane, Sissy Spacek, Will Arnett). Too bad the plot takes a back seat to become a random vanity project of humorless sketches for The Lonely Island and the awful acting of lead Andy Samberg. The plot takes up maybe 15 minutes (at most) of the 83 minute run time.
 * The film adaptation of S.W.A.T. had amazing potential: A European drug lord offers "one hundred meeeeelion" dollars to anyone that will break him out of the LAPD's custody. A series of all Los Angeles' wacky residents and their schemes would have made for a far more interesting film then the generic action movie and revenge plot that we got.
 * The movie Hot Rod has an interesting concept (wannabe daredevil decides to raise money to help his father get an organ transplant and win his love) and a decent supporting cast (Isla Fisher, Ian MacShane, Sissy Spacek, Will Arnett). Too bad the plot takes a back seat to become a random vanity project of humorless sketches for The Lonely Island and the awful acting of lead Andy Samberg. The plot takes up maybe 15 minutes (at most) of the 83 minute run time.
 * The film adaptation of S.W.A.T. had amazing potential: A European drug lord offers "one hundred meeeeelion" dollars to anyone that will break him out of the LAPD's custody. A series of all Los Angeles' wacky residents and their schemes would have made for a far more interesting film then the generic action movie and revenge plot that we got.