He thinks bringing a fresh look to the character is a GOOD thing and I have to say that I agree.
I'd prefer that they don't just replicate the white-face from the first Burton Batman movie, although the image above, which is from the short film Batman: Dead End is a pretty cool incarnation of the character.
Seeing the cool job Nolan did with the Scarecrow character in the first film, I'm looking forward to what he'll do to Heath Ledger in the sequel as far as makeup. I have no doubt it will be the creepiest incarnation of the Joker to date, and that he will be particularly psychopathic in nature. I'm pretty sure the character will cause the film to push the boundaries of the PG-13 rating.
Source: Batman on Film