In the first film the League of Shadows wanted to destroy Gotham for it was corrupt and a mess politically and was leeching off the bigger system or something of that sort. In the second film with Harvey Dent's death and Batman taking the fall for it so the Dent act would get passed, Gotham's streets were cleaned up, people fell in behind this face that represented what was good for them; in effect getting rid of the problem the League of Shadows had with Gotham in the first place.
Just because a lot or most of the obvious criminals in Gotham were locked up does not mean that the politically corrupt or better concealed criminals weren't. That is apparent by the corrupted leaders working with Bane in the first place. I doubt that they would be considered good enough for the no tolerance league of shadows.
But even then that is not the motivation behind Bane and Talia, they were to get revenge on Batman, and not to break his body but his soul by showing that he lost. Making him watch everything that he had worked for be destroyed. Talia was the daughter of the original leader of the league of shadows, so she didn't care as much about the ideals of the league of shadows as much as she did care about getting revenge on Batman.
Another problem I had with the film were the inconsistencies. Gotham was on lock down. How did Bruce Wayne make his return? I felt like there were a major few scenes missing. And how did he conveniently find Cat women so easily?
Bruce Wayne made his return because he is freaking Batman! He is a trained ninja, and all he ever does is sneak around, that's obviously how he got in. Not to mention the new found will from being inside the pit. How does any character in any movie also seem to just "find" the other so easily? It's because they don't want to waste time slowing the plot just to show how he tracked her down. Honestly, i've never seen a movie where we had to literally watch them leave one scene and track down the next character they meet with.
Also his scene in the pit was somewhat rushed. I wanted to see him go through hell. I wanted to see him work up to climbing out of hell; to actually rise above the fire they spoke of so fiercely through the whole film. His experience seemed far too simple and plainly easy.
He was in the pit for a large chunk of the movie. What did you want them to add, another hour of wallowing in the pit for effect? Ask for it in a director's cut edition but thank God they didn't do that for when I watched it. It was just long enough to get the point across. I don't want to judge but it seems like all these plot points can be filled with just a little bit of imagination. Sometimes it's better for movies to not hit you over the head with answers and just answer the questions yourself.
An actual argument can be made for someone who only watched the movies though, and that's where is joker? I thought they released all the prisoners, even Scarecrow was released, so where was joker? He would obviously want in on the action. I bet they would have made him be more involved in the movie had Heath Ledger not died, but not mentioning him at all didn't seem like 100% the right thing to do.
Edit: On topic, I found the movie to be amazing, way better than I thought it was going to be. The whole trilogy is the epitome of superhero movies in my opinion. They have a sense of semi-reality that is a type of immersion that no other super hero move has ever done. Yeah, it's not 100% realistic but it makes sense for the most part and gives decent explanations even if science can prove some of it wrong. The point is that if you go in and watch the movie just for entertainment and not just trying to criticize it, it is easy to get lost in the plot, characters, drama, and action.
