I say that in all seriousness. I think if Bruce dies in the 3rd movie it would be the perfect cap to arguably the best comic book movie series to date.
Fans have been saying since Begins, The hyper-realism of Nolanverse leaves little room to explore the other, more far-out elements of the Bat mythos, that and Nolan himself has said several times there are characters and elements that have no place in his world and he never wants to use them.
I say fine, let someone else come in and do their own Batman their own way. But after Nolan leaves don't do us the disservice of making a "pseudo-sequel" a la Superman Returns & Batman Forever where no one but the director knows for sure whether it follows anything that came before. It's a ******** gimmick that causes more problems than it solves.
since this is kind of an elseworlds Batman story, there's no reason to keep it open ended like other stories. Unlike the previous series, Nolan's movies form a much more cohesive narrative, and that narrative needs a true, definitive ending in order to feel complete. How would any of you feel if they changed the ending of "Return of The King" in the hopes of milking a 4th LoTR movie? The height of absurdity, right?
It's almost a sure bet that Joker won't be back without Heath Ledger (as it should be), but the ambiguity of Two-Face's fate means he can be brought back without much difficulty. This serves several purposes:
1: Gordon & Batman's worst fears are realized, the myth of Harvey Dent is shattered as Gotham is forced to face the ugly truth and uglier face of its once revered savior
2: It means Batman can be vindicated, at least in the eyes of the public, they might finally realize that Bruce really was the hero they deserved AND needed all along.
3: C'mon... Two-Face is too good a villain not to give him a chance to wreak major havoc
Two-Face should go for broke, he should be hell-bent on burning Gotham to the ground (or at least half of it). During the course of the action something will happen, and Batman has no choice but to rush headlong into a situation he knows he probably won't survive, but he never wavers even for a moment, as long as he can draw a breath Gotham will survive. Two-Face is finally defeated and dies conclusively as Bruce dies as well.
He lived as a warrior, let him die a warrior's death. Alfred remains to tell the story and set the records straight. In the end Bruce Wayne did just what he said he'd do back in "Begins," he returned long enough to show his people their city didn't belong to the criminals and the corrupt.
You could tell me I'm crazy, but I know I'm not. How ballsy would that be, if Nolan had the guts to kill off the hero in the end? And not just any hero, THE GODDAMN BATMAN!