Reshoot Batman's Dialogue
If Heath Ledger had been alive, as director I would have had several test screenings to see if the audience had any problems with understanding Batman's speech and if so consider reshooting or at least dubbing his lines so that the audience might have a better, if not absolutely clear understanding of what he said. Or on the otherhand, reshoot or dub this speech so it was more obvious that the audience wasn't really supposed to understand what was being said and just let the action speak for itself.
Powerful Emotional Dilemmas
What seems to set this movie apart from other like movies was its intensity and multiple focus on emotional conflicts between good and evil and between the lesser of two evils. There was not clear right or wrong, there was a lot of gray, like real life. In addition to the action for action's sake there was a building, underlying riveting internal debate of having to make decisions where something bad was liikely to happen, evil was taking over, Batman suffers mightily and like a martyr, he suffers (perhaps needlessly) his public image, like an honorable Japanese warrior. This is what was most impressive despite the flaws in this movie when I watched it a second time.