I think to some, TDKR would never be as good as TDK.
Joker is THE villain of Batman. Ledger portrayed a phenomenal self made interpretation with Nolan and clear influences from various different material. Joker brings out the duality, the psychology of Batman. Two of the same, but opposite ends of the spectrum. The purest good and bad fight you can get.
Bane doesnt have that sort of character. Bane is harbinger of battle, of war. He is the ultimate physical opposition next to Rhas. Bane is very intelligent, but IMO I never thought he would be capable of holding an entire film together, but I cant wait to see the performance of Hardy, and it will be awsome.
I always thought that Rhas would come back and Bane would be his right hand man in the Nolan films. Bane doesnt have the visual impact, doesnt have the psychotic nature, the flipping of the switch that joker, and Ledger, portrayed. I think that will be the only problem that would ever happen with TDKR.