I also find it fascinating that Nolan's trilogy seems to say that having a superhero vigilante is actually NOT a good thing. Especially with TDK and TDKR. (BB was pretty idealist and comic-booky in its "Yeah Batman is a hero wooo!" rhetoric.)
In TDK, Batman's actions cause the very situation that allows Joker to gain his power through the mobs' desperation. And it's arguable that Joker would not exist if Batman didn't exist. He questions Batman's reason for being.
In TDKR, Bane and Talia (as well as Alfred) point out Bruce's reason for being Batman and how unhealthy it is. That it's too much responsibility to bear on just one person's shoulders, especially someone as damaged as Bruce. He draws his very identity of being heroic. What happens to Blake is yet to be seen, but we do get the idea that he doesn't base his entire identity on being THE hero. He just does the right thing when he can. That's what he can offer to Gotham. Whereas Bruce has the capability of offering so much more and chooses to be Batman and put himself through all that pain instead. At the end, when he turns Wayne Manor into an orphanage and gives Blake the tools he needs to continue to do the right thing, he's finally stepping aside and giving other people the resources to do good. That's what society needs - the opportunity for good people to do their work. Not one superhero who's going to save the world all by their lonesome. Because it's simply too much responsibility.