Proactivity is what makes Bruce Wayne Batman. He doesnt wait for things to go down, he doesnt hang up the cape and cowl simply because the denizens of Gotham arent his biggest fans. Batman doesnt care; all he knows is that Gotham needs a Batman. He views everything else as secondary. Fair play, Nolan has seemingly lifted the 8-year sabbatical that Batman has been on at the beginning of TDKR directly from Frank Millers Dark Knight Returns, but like so much else its been rather clumsily forced up the backside of the franchise without lube or even a courtesy spit. Millers book was a What If response to the overwhelming outcry caused by the main canon death of Robin at the hands of the Joker. It was a response to the death of a child in his care. In TDKR he left Gotham to its own devices simply because it asked him to. Thats just not copacetic. Then, he abandons Gotham for a second time after he somehow escapes the blast from Banes nuclear bomb becausewell, you give me the reason. Whatever it is, it surely isnt good enough to justify why Batman leaves the GCPD to round up every escapee from Blackgate (addressed by a couple of quick shots of them arresting a few guys that explains 5 or 6 of them I suppose) and leaves a complete rookie in charge of the Bat legacy. Some theories even dictate that the vision of a living Bruce Wayne in the closing scene is merely Alfreds grief-stricken hallucination a dream within a dream if you like that he actually died in the blast. And if you can stomach that, you can stomach anything.