Re: In hindsight what changes would you do
Did Joker win the battle for Gotham's soul at the end of TDK? No. Did he manage to bring a better class of criminal to Gotham like he wanted? No. So he didn't win. His victory was covered up with a lie.
Bruce: "The Batman wasn't needed any more. We won"
Gordon: "Based on a lie"
It may have been based on a lie, but they still stopped the Joker from winning.
"Sometimes I remember it one way. Sometimes another. If I'm going to have a past, I prefer it to be multiple choice!"
- The Joker