The issue for me is that Bruce Wayne is a driven personality, he requires strength, conviction, AND obsession. He doesn't just stop being what he is (Batman, among other things.) The depiction in the Nolan films shows someone who used the Batman persona temporarily to make a point and then fucked off. Kind of like an internet message board identity. It's not who he is. For Bruce Wayne to be Bruce Wayne/Batman, he should be thoroughly committed.
I appreciate in the Nolan universe that Bruce Wayne essentially fell apart when he stopped being Batman. His psyche is intimately tied to Batman, and to Gotham. If Gotham ceases to be, or changes radically, so too does Bruce Wayne cease to be. This is a pretty clear portrait in the story and kudos all around. That said, Bruce Wayne exists because he has extreme personality disorders, just like the Joker, et al. He doesn't just happen to stop needing to have the Batman persona to be able to deal with his personality needs.
You are talking about one, very particular interpretation of Batman But it's just one among many. You may like it best, but that really only matters to you.
For instance - I heartily disagree that Bruce Wayne has extreme personality disorders. Yes, the character has been portrayed that way - this was begun by Miller's the Dark Knight Returns, which most people forget was the story of a Bruce Wayne whose personailty had become distorted by years of impotency while Gotham City disintegrated around him. DKR was the Batman of the 70s (a supremely rational man) driven to the brink of madness by circumstance, not because he has inherent personality disorders.
Unfortunately, this interpretation got picked up and proliferated across Batman stories of the late 80s and 90s. But if you go back to the 70s, the years of Batman as the Dark Knight Detective (and this version seems to be by far the nearest to Nolan's interpretation), Bruce Wayne is first and foremost a clear-thinking and ingenious tactician, who uses fear to gain an advantage in battle. He is dedicated and driven, surely, but he is not obsessed. He has made clear choices in life - I will give up many things about a normal life in order to fight crime, but it is no more than a dedicated cop who decides never to marry gives up.
In saying this, I like the story, and I don't. It touches the reality of the obsession and need, then it backs away from it. I don't feel it totally works as a character study.
It probably does - it's just the study of character who ends up not really being that interesting. BBegins and TDK seemed to be telling the tale of a man who makes a pretty out there decision to try to shock an entire city into straightening up. It ends up working for a bit, then going badly due to the introduction of a force of chaos equal and opposite to the force for order that Batman is. The story of the character at this point is strangely heroic/tragic - Bruce wanted to exorcise his demons and lay down the cowl for personal happiness, but it seems at the end of TDK that he has come to accept a darker destiny: to endure, to be the dark hero that people may hate but who will work nonetheless to save them all. That's a pretty interesting guy and a pretty interesting story.
Then TDKR opens and we find out that rather than enduring and continuing in spite of hate - he sulls up in his mansion and pouts. Because he is personally attacked he reenters "the game", loses the city to terrorists and manages at the last moment to stop them from blowing the place sky high (though not managing to stop a great deal of misery in between). So he pats himself on the back, grabs a hot chick and retires for good, leaving all his cool gadgets to someone else - to do what with is entirely unclear.
Not so interesting of a hero after all.
But it really doesn't have anything to do with how obsessive or not he is - especially since that's an interpretation of the character that is beside the point of the tale Nolan was telling. The trilogy, however, ends up not being a particularly powerful story even judged by its own internal rules.
