I think he's dead. I think if he was alive we would have had Wayne and Gordon commenting on how he'd need to be kept hidden away from everyone, or something. There would have been SOME concern about it on-screen.
Also, I think it was established earlier in the movie that Batman can take moderate-height falls better than other people can, specifically when he dropped Sal off the building.
On the flipside, Two-Face is one of Batman's greatest nemeses; really only The Joker is a bigger deal. And as Miriel said, they sure as heck ain't recasting The Joker until they make some new Batman movies twenty or thirty years from now.
But I still think he's dead, to be honest.