Not ruling anything out, but that would be a depressing end and leave Bruce's actions for naught.
This is the sort of ending I'm expecting. It isn't a happy ending, not for Bruce. Maybe he does find some sort of resolution, some sort of conclusion, but it doesn't have to be a happy one.
I just can't see Bruce ever finding joy, living a "normal" life. I said once before that, even he did stop being Batman, that I think he should leave Gotham. Two reasons for this:
1-As I've said before, having him just stop being Batman, especially as he is "retired" at the start of the film, seems stale to me. Even if there was emotional growth for the character, there is no real change in the status quo and the movies don't seem to be about that. The first film was about Bruce becoming Batman, the second about Batman becoming The Dark Knight (and, as we learn in third, stops being Batman). So there will need to be a change in the status quo that will need to, shall we say "rattle the cages." In essense, he is no longer Batman or Bruce Wayne.
2-Gotham will, no doubt, be a place of darkness for him. His parents died there, the love of his life and a good man died there. And if the body count raises even more in this one? Even if Bruce does save Gotham, odds are good he will always relate it to the negative things in his life. He loves Gotham, of course, but he must hate it too. Ultimately, showing Bruce Wayne leaving Gotham shows him moving on with his life.
But I keep coming back to the title. Rises. The Dark Knight Rises. Obviously, the rises is refering to Bane's (for lack of better term) revolution in Gotham. But The Dark Knight has to rise too. Does he rise from the shadows, returning to Gotham after an 8 year retirement? Does he rise like a pheonix, returning after Bane had him beaten and broken? Does he rise in the eyes of Gothamites, now being viewed as the true hero of the city, who has sacrificed his life?
But it's also "The Dark Knight" that rises, not "Bruce Wayne". So maybe the film ends with the death of a man (Bruce) but with the rise of Batman as a true symbol and a legend?
Ultimately, these are all guesses. The truth is, Chris Nolan could do any of the three basic ends (Death, Retirement, Continuation) and would find a way to make any of them work. Certain variations may not be happy, and maybe they shouldn't be. Honestly, I don't want Bruce Wayne to have a "happy" life. Everything he's done in his life has been about sacrifice, putting others ahead of himself. I don't know if he could ever be happy.
I've said before I compare Bruce to a soldier returned from a tour of duty, not certain what to do with his life and maybe always itching to return.
Anyway, I'm talking in circles at this point. This has just been a stream of conciousness but maybe someone will get the general idea of what I'm going for.