I really wish Two-Face hadn't died.
He could have easily just been knocked out by the fall, or in a coma. With as corrupt as Gotham, and probably Arkham is, Gordon could have easily put a hood on Dent's face and hid him in Arkham. Plus, now that Arkham is the entire area of the Narrows, it'd be WAY too big for anyone to even bother looking for him even if there WAS an inkling of suspicion about Harvey's "death."
Could have been in a coma until TWO-FACE, not Harvey Dent, TWO-FACE, woke up. Then all that would have motivated him was death and the obsession with chance. Killed a guard and/or doctor and escaped. Organize a freak uprising against the dying mob(and there WILL be freaks, Batman's and Joker's antics made sure of that) and finally rustle control away from the mob and into the hands of the new breed of Gotham criminal.
Just would have made things so much easier if Two-Face had survived in the script. Nolan could still bring him back, but it would messy and complicated. He could do it, but I'd rather it be smoother.
Of course, Two-Face would be working behind the scenes. Making deals with the new freakbosses. Roman Sionis, head of whatever company he was head of by day(the anti-Bruce Wayne), Black Mask, the new head of Gotham's organized crime by night. And Penguin, the official gun runner and racketeer of Gotham's criminal underbelly. The combination of mob boss and freak.
They'd have about the same sized roles as Maroni and Falcone in TDK and Begins. Throw in some cameos by Killer Croc as Penguin's body guard or what have you and that works for that.
The main villain should be Riddler. We've seen Batman's rise as an urban legend and the sacrifices he's made in becoming the champion of Gotham, now we need to show off his super-intelligence and detective skills, which was hinted at in both Begins and TDK(TDK to a much bigger extant).
I need to stop before I set out all my ideas, which will take all night.
