I think Nolan will end the series in a satisfying if slightly shocking way. I don't think he'll do anything for pure shock value, but I think he'll end it in a way which will be unconventional and yet ultimately satisfying at the same time.
I don't think Bruce will reveal himself as Batman, even though things were leading that way in The Dark Knight
, but I do have a strong sense that Bruce will give up the mantle or realize that he can never give up the mantle and must be Batman forever (hey, what a good title for the third installment... oh, wait, nevermind...). I think Nolan likes somber endings and I know he thinks Batman is a tragic character, so I can see an ending where it is somewhat hopeful yet tragic at the same time, with Bruce slowly and gradually realizing he must be Batman.
I think the ending of The Dark Knight
was implying that, with him on the run as a vigilante. It's a plot point that's been in development since Batman Begins
.... that he's not a vigilante, that he's something more, yet now he is exactly what he didn't want to be. So unless Nolan reverses that cycle, I think a big part of the next film will be Bruce coming to terms that he is