Batman as Wish Fulfillment
It's been stated that Batman as a hero has never grown stale or supposedly never has anything to worry about and will always be the fan favorite (in some circles at least). This always bugged me on just why fanboys consider batman to be so great. Finally, a solution was found: Batman is an airtight form of wish fulfillment that doesn't age in our current cultural context.
Batman is Badass Normal. Already he's fulfilling the realistic wish of so many. We know we can't fly or aren't super strong or super fast. Batman though is a hero that supposedly, "could be you or me." (from Batman: Unmasked) He's our projection of accepting our limitations, but still reveling in how far we can take it.
Second, batman has the whole Dark Is Not Evil and Good Is Not Nice bent going for it. Mankind longs to be good, but at the same time we applaud the swift and brutal defeats of those in the wrong. Batman does both of these things, and yet still remains a good guy for not crossing the Thou Shalt Not Kill line in modern times.
Third, Batman is the paragon for our love of cunning and intelligence. True, he doesn't exactly have an alien encyclopedia, but the notion of being Crazy Prepared for the future in the chaos of real life is extremely appealing, and Batman can somehow do it without seeming silly or having Fan Dumb screaming Ass Pull.
Fourth, Batman is our selves rising above reality. Batman lost his parents at a young age, but sought to go forth and create a new order no matter the personal cost. This is extremely admirable as not only has he moved forward to higher causes, but he's doing it in a manner that we enjoy watching. (Heck, his charitable work as Bruce Wayne is practically a footnote compared to what Batman has done, but perhaps that's just the way comics work)
Fifth, Batman operates in a Crapsack World in order to better perfect it as his old home. Sure, we might put on airs to help save the world, but Batman is going out and making a truly depressing world better, and his Tragic Dream is something many admire.
Batman's Rogues Gallery as a reflection of the hero
Batman is generally considered to have one of the best, if not THE best, Rogues Gallery in comic books. This Troper posits that part of the success of Batman, and part of the contribution to his legendary status, is that his Rogue's Gallery is such a perfect shattered reflection of Batman himself.
- The Joker: He represents the chaos and dark impulses that Batman struggles against every day—in crimefighting and within his own mind.
- Two-Face: Represents the struggle between dual identities inherent in Batman/Bruce Wayne's psychology.
- Riddler: His obsessive-compulsive and self-sabotaging traits reflect back the obsessive and possibly self-destructive side to Batman's own personality. His championing of intellect to commit crimes also reflects Batman's detective abilities and his use of intellect to solve them.
- Scarecrow: His main tactic is to rule through fear—similar to how Batman cultivates a frightening persona to intimidate crooks and hoodlums.
- Penguin: Penguin acts as a rich socialite, while actually acting as a crime lord or black market smuggler. Similar to how "Bruce Wayne" is an act for batman, only he does so as a Rich Idiot With No Day Job while also acting in philanthropy rather than descending into criminality.
- Man-Bat: This is the danger the Batman has if he errs too far on the side of being the Bat without remembering the man.
- Catwoman: Uses an animal motif to get what she wants, and is highly athletic in using said motif. Also, both rose from personal tragedy. The Not So Different and Dating Catwoman parts of this contrast make both very strong foils to each other, particularly in the fact that Batman keeps trying to reform her.
- Poison Ivy: Like Batman, fights for what is ostensibly a noble and socially admirable cause involving protecting those who cannot protect themselves; however, Ivy goes too far and becomes a Knight Templar who identifies too closely with her cause and cannot see past it to the point where she ends up causing just as much if not more suffering than she prevents.
- Mr. Freeze: In his more modern incarnations at least, has suffered the brutal loss of a loved one that has subsequently defined his life in the same way that Bruce Wayne losing his parents defined his.
The analysis can go even further, in that like Batman himself many of Batman's enemies have either ostensibly sympathetic back-stories or some inciting incident in their past that motivates their actions, just as the murder of Bruce Wayne's parents is the primary motivation for his actions as Batman. However, where Batman uses this incident as a motivation for trying to make himself and the society he lives in a better place and to prevent what happened to him from happening to other innocents, his enemies have all succumbed to despair and madness, and instead use their traumas and pain as an excuse to lash out and hurt others.