Topic on Talk:Designated Hero
Watching the video again, it seems to me that Meggy is the only sane woman among all characters, whereas all others are Dumbasses who don't really know what they are doing.
Also notable is the sudden tone shift during Mario's final attack. Previously nonlethal gun wounds are suddenly instakills, and a fall out of the window suddenly becomes deadly when it wasn't before.
Pretty much everyone over-reacts comically and there is a lot of Trigger Happyness on both sides. Their dumbassness may make the other characters more lovable and their atrocities more redeemable. Meggy may seem over-powered due to being more intelligent and less emotionally volatile than the rest.
This may have been interpreted by my brain as, she is manipulating her team and cruelly abusing her intellectual superiority towards Bowser's clan. Also thanks to the Fridge Logic that she has no real motive to join Mario, apart from having action (making her a Type II Nominal Hero). Mario, by comparison, is a Type I Nominal Hero, since spilling his Spaghetti seems to cross his Moral Event Horizon. (Bowser, as seen from the other side, would also be a Type I).
As for the incident with Wendy, this is most apropriately called a Shoot the Dog moment, paired with a near-Senseless Sacrifice since it should have been easy to overpower her in a non-lethal way (just omitting the Finishing Move when she's already downed and instead keeping her in check with Meggy's weapon should have done it). Either way, the plot is cooler with Meggy's Finishing Move, as long as you don't think about it too hard. Wendy's own heavy armament acts to further downplay her helplessness and despair. Also, for anyone sympathizing with her, it wouldn't have made things much better if she was left alive as the only remaining Koopaling.
All of that actually changes nothing with respect to this trope. Heroic characters forming a criminal clan as a response to a misdemeanor and attempting to Kill'Em All definitely qualifies, no matter who of them is the worst now. (Anyways, everyone breaking into the heavily guarded lounge of the hotel isn't that smart of a plan. Bowser's survival also carries its own Fridge Horror, as he may become enslaved as a cook, and he doesn't yet know that he's just lost his entire Patchwork family.)
What may be "autistic" about my spontaneous interpretation is that I'm judging actions, not characters, even when the plot makes it clear who is supposed to be the Good Guy, that I dive deep into Fridge Logic in a video that is meant to be lighthearted entertainment, and that I'm generally taking a nonsense plot way too serious.
Possibly also some unconscious Clang association, in so far that Wendy's sounds in here remind me of a crying child, causing an unwanted sympathy effect. (Though I'm not generally sympathizing with said character.)
Unfortunately, this video has no sequel - that would really be interesting. Think about some Police Are Useless hunting down the team, and when convicted Mario escapes into the forensic lab and resurrects everyone with 1-Up mushrooms - or the like. Similar things happen in other SMG4 videos where characters are apparently Killed Off for Real first. The relatively realistic scenario without any subsequent insertion of Video Game Logic like this is also a reason why this video is a rather dark one. And why one could feel sympathy for anyone who gets killed.
Lol answered my own questions.