Originally Posted by Mr. Wooden Alligator
For all your talk about Nolan eschewing imaginative villains and fantasy concepts, I just don't see it. Joker's backstory - "You wanna know how I got these scars" - and overarching goal are straight from the comics. The backstory is a direct reference to his preference for a multiple-choice origin, while his overcarhcing goal is adapted from The Killing Joke; replace Jim Gordon with TDK's Harvey Dent. I don't believe that you could look at Nolan's Two-face and honestly tell yourself that the scarring isn't a fantasy concept. A guy that badly scarred shouldn't be near as vocal as Dent was, and would likely have screamed himself raw after throwing back that shot of whiskey.
Nolan's last 'realistic' movie was Insomnia. Everything since then has delved heavily into scifi/fantasy. Even his Turn of the Century period piece gave the main protagonist a cloning machine.