Oh bullshit. I love TDK, but they only ever made it about him at the end, tying it in a nice little bow and saying "uh, here, he's living martyr!"
The movie was entirely about the negative forces that he brought out, particularly the Joker. Batman is a ridiculous entity, and so he brings out an equally ridiculous source of evil. It was the Joker's show throughout the entire flick and his affect on the system, proving his own points. The Joker might have gone to Arkham at the end, but he definitely won.
I'm pretty confident, though, that the next movie will be either about Batman's downfall as a hero, or his redemption.