That's been my main question about him; why is he trying to punish Bruce/Bats? What happened to Bane that makes him want vengeance against our hero? I'm sure a lot happened in the 8 year gap since The Dark Knight, and perhaps it was something during that time? Perhaps we will see the return of the League Of Shadows, this time with Bane as their "ace in the hole." Perhaps Bruce must be punished for stopping them the first time around. He allowed everything that happened since Begins to take place, and perhaps the city got much worse. I know that in the trailer it says they are at a time of peace, but we do not have context for that and we don't know when that started. That would be the trilogy coming full circle and returning to the idea of tearing a city down once it's reached its pinnacle of decadence.