first I played through Normal and thought it was challenging were it needed to be then I tried hard and realized that I AM BATMAN and it was piss easy and New Game + in hard was, okay I guess, bosses were just as easy as normal and for some reason large group of enemies (Joker boss fight, Hugo boss fight, etc.) were kinda easy once you realized that all henchmen have the same animation for attacks and you can counter everything
Clayface gave me a hard time in normal in hard and +hard he was one of the easiest bosses, I dunno maybe its a first time thing