Nolan's batman movies did really well and they had more "grounded" villains (well, so long as you ignore scarecrow, ras al ghul, bane, talia al ghul...), so this one tried to follow the same trend. It also apparently brought in Nolan's tory politics and utter contempt for the poor. Remember when Bane stages a people's revolution in Gotham only to then decide he's going to nuke the city for no reason?