More like mainstream perception than idea but I never liked how Robin is perceived to be a joke character just because he's the sidekick. He adds a lot to the table. Can do a lot of things Batman can't and is usually the one who has to save Batman from himself when the situation calls for it. It grinds my gears seeing his value overlooked like that.
I never liked how the Joker is the only villain that's allowed to hurt Batman and his allies on a personal level. Batman has other villains that are perfectly capable of doing the same but never get the chance. I liked it when it was Bane who killed Alfred, Scarecrow being the one who forces Bruce to expose himself to the world in Arkham Knight, Talia being the mortal nemesis of their son.