I think most would agree with me in saying Batman overall has a really solid Rogues gallery. I like Poison Ivy, I like Harley Quinn, I like Riddler and Penguin and Freeze I like Scarecrow, Man-Bat, and Mad Hatter.
My favorite, and the one I think archetypally challenges Batman the best is Two Face. Two Face can be seen as a sort of court vizier become a plotting sorcerer. Harvey Dent meaning something to Bruce Wayne before he is ever Batman, and means something to Gotham. Dents arc as prosecutor who flies too close to the sun and is burned for it, falling not just down to earth but down to Gotham, where he becomes a twisted amalgam of the sort of judicial logical reasoning he was practicing as a mechanism, is a good counter thrust to Batman in a metaphysical sense. It is also necessary that Two Face doesnt try to commit or justify mass murder or terrorism for its own sake, he does exactly the type of outfit-style crime he prosecuted as Harvey Dent, and throws a monkey wrench into the process of it by using his particular brand of logical realism to inflame the situation. A man who was twisted and broken and finally led into an existence of parallelism to his former life by personal tragedy is in itself an expression of Gotham city- and Batman.
I would say a bad Batman villain is Firefly or Deathstroke, also Deadshot or Szasz. Not that they are bad characters necessarily, but I think they would be better served in other places in the grander narrative that we have thrust upon us. Being a hitman or assassin who is for some reason an independent actor seeking vengeance on Batman for a job gone wrong over and over and over doesnt make you a good Batman villain candidate- it makes you an unprofessional hitman. Deathstroke as a Batman villain is a refutation of Deathstroke as a character. The worlds greatest assassin is not the worlds greatest assassin if he has the baggage of being a Batman villain around his neck- he needs to be doing other shit! Like actually getting away with killing people! Put him in Nightwing’s rotation and actually take it seriously, theres a million ways to do this. Maybe Deadshot is on the Suicide Squad all the time for a reason. What is the point of having him in Gotham, literally ever, after the first 3 times Batman puts him in prison because Deadshot can’t kill him. Would a guy whose main goal it is to get rich doing what he is good at not just try and kill literally anyone else anywhere else if Gotham had Batman in it?
90 years of Joker comics have inured me to “psychos” in Gotham. The original Joker appearances I think are cool and have an interesting thing going on, I like that he comes back from certain death over and over. This makes much more sense to me than him being in Arkham pretty much at all, because the sort of shit he was getting up to back in the day was like “Gassing a room with the chief of police and mayor in it, then their friends every hour for 12 hours! Hee hee!”
But fundamentally I think Joker as a character is overused, has too much stimulation for there to be meaningful interaction with the character, he has simply been done to death, they should literally kill him and just leave it. Theres a path to be walked with the consequences of Harley Quinn, who many agree has become entirely obnoxious, that to me is not dissimilar from my thoughts on the Joker.
I think it can be fun for Batman to stop psychos and Gotham should have them I dont mean to say that Batman villains shouldnt be crazy, but put Szasz and Firefly in Hub City and start writing Question Comics again with some vigor.