An "evil Batman" story could work but similar to what True Detective said, you can't just apply the "Evil Superman" formula and apply it to Batman. I think it'd have to be something far more small scale and it'd be something like taking the idea that stuff like White Knight dances with even further in that Batman, in-universe, does choose intentionally choose to go after the poor/mentally ill or Kingdom Come where he turns Gotham into his own little authoritarian state.