Ya know, Christopher Nolan could have totally given the role of Joker to JGL after TDK, and it would have worked. JGL is a pretty good actor, I'm sure he could have pulled it off.
I mean, I'm glad he didn't, because having the same villain in 2/3s of the trilogy is just fuckin lame. I'm just saying it totally could have worked, and JGL is in TDKR anyway. So yeah.