I think two fan edits could resolve the problem for me:

1) Slightly rearrange the ending so that all the hinting at Bruce's possible survival remain, but that the last shot is Alfred looking at the camera, smiling, and nodding. It would still be slightly ambiguous, much like Inception, where we're pretty darn sure that we know everything ended up happy, but there's just a teeny tiny bit of doubt.

OR

2) Cut all references to his survival and simply imply that John Blake took over, thus strengthening the message that Batman's a symbol, not a person, and that even with Bruce dead, Batman lives on.

Personally I favor the first option.

Nevertheless, I still really enjoy the film, despite a slightly weakened ending. I feel it could have been slightly better with one of the two endings I mentioned, but as it is, the true ending does not damage the film too seriously for me.