Yeah, I think it's probably going to be another "rise of villains" movie. Joker portrayed a very different character than old portrayals of the character. There wasn't any "fall into vat of acid", it was simply "here's a clinically depressed, unstable person who worked as a hired clown", and the trademark white face was just greasepaint.
The problem is that none of the other villains really can be re-imagined that way. Two-Face was burned, but burn victims just have featureless, flat faces (basically a skull covered in pale flesh), which don't really work because so many nerves get simply burnt off. The Penguin is just an overweight deformed midget with a bird obsession. Ra's al Ghul is an immortal with a taste for genocide. Poison Ivy is a literal mutant, Killer Croc is probably a mutant, the Scarecrow is a Scooby-Doo villain with chemicals that really aren't possible in reality, Mr. Freeze is basically a dying man in a supersuit, Zasz is just a sadistic murderer, and Bane is, well, a big guy (for you).
But half of them (generally the more plausible half) have already been given over to a new origin story in the Christopher Nolan films. Bane needed a reboot to be closer to what he was in the comics rather than a muscular grunt in a lucha libre mask like he was in Batman Forever. The only villain I can see that can get a Joker-style reboot is the Riddler...who already is damaged goods. He's straight out of the Silver Age, his costume is ridiculous, his origin story is already pretty down to earth (DCAU showed him as a computer programmer screwed out of his job), and at best he's an intellectual equal to Bruce Wayne.
