Total agreement, over here. Arkham Asylum is a great game, make no doubt about it, but when the setting of your game is the prison complex that holds nearly fifty of comic book's greatest villains, to only have a handful of them make appearances. I'd probably forgive that, too, if several of them weren't just cameos or copies of the same fights you always have.
Note to gamers: when someone shoots you in the face, they aren't "gay." They are "psychopathic."