thenammagazine
Super Freak
I wouldn't call a more realistic (for lack of a better word) approach to the superhero genre as lacking imagination. Quite the contrary. We've had many fanastical takes on the genre but I can't think of any movie aside from Unbreakable that tried to play it straight prior to BB.
He didn't think Killer Croc, Penguin, Clayface, or any of Batman's other more fantastic rogues would work. Just looking at what he did to the Joker reinforces this. He had to fundamentally change how the Joker looked to fit him into his, for lack of a better term, "more realistic" environment. Now that's not saying it didn't work. It did, in the context of the films. But that's not to say he didn't run from the prospect of something along the lines of Hulk.