A love interest. Batman isn't James Bond. He doesn't need to have a girl in every movie like he's had so far (even if the latest one rejected his advances). I'd be okay with BRUCE WAYNE having a token girl or two like the Russian ballerinas in TDK or the hotel girls in BB, but a serious love interest takes up valuable story time that could be put to better use elsewhere. And it's even worse when the girl knows/finds out Batman's secret identity, which has happened in every Batman movie except for B&R. 
Edit: I guess you could even count B&R if you take Batgirl into consideration, even though they weren't romantically involved. I pretty much don't want anyone finding out his identity unless it's Dick Grayson (not going to be in Nolan's movies) or MAYBE Gordon. I guess a villain could discover it, but even that's starting to become cliche in superhero movies.
		
 
		
	 
^This!  Part of Batman's appeal, at least to me, was the idea of a guy who has everything, while really having nothing.  
One of my favorite all-time scenes is in BR.  I never particularly liked BR because of all the weird things Burton was doing, but I grew to appreciate it on it's own terms.  
But one thing I did love about it was the portrayal of Bruce Wayne.  The scene where he's just sitting in the dark, in complete silence, until the signal shines and gives him life just resonates with me.  This is a man who's lost just about anyone he's ever been close to, he's dedicated his life to an impossible vision.  Because of his existence, he's responsible, directly or indirectly, for the very evil he's trying to battle.  This is who Batman is to me, that's the stuff that makes him everlasting, and the greatest hero of them all.  Someone who doesn't really have to do it, but still 
has to do it.  He doesn't have a life anymore, his life is Gotham City.
I understand these are the beginning years, but after BB & TDK, I'd like to see a Bruce Wayne who understands what he's gotten himself into.  Having any type of love interest is dangerous, plain and simple, no matter who it is.  And beyond that, it's a distraction.  The Cave is his sanctuary and the cowl is his true love now.  Rachel hinted at it in BB, but they need to make it real now.  My ideal Bruce Wayne isn't Bruce Wayne at all, he's just the Batman now, sitting in the dark, waiting for the signal to shine....