Re: The Dent Act
I too preferred the sparsity in how they dealt with the Dent Act in the film. The two scenes in which its changes are discussed don't feel like force-fed exposition, which we know Nolan is sometimes guilty of. One moment (Selina being thrown in Blackgate) provides us a fun badass Selina moment, the other (Blake and Gordon) is a character driven, emotionally charged moment. It's enough to give you an idea without beating you over the head with it and making the film drag. No amount of exposition is really enough to give you the full story of 8 years, so I think the film was wise to avoid trying to explain it to death and leaving things to the viewer's inference and imagination. Too much explanation would violate the illusion of the passage of time I feel. The way it's presented in the film, it just feels like "this is the way it is", and Gotham has been living under these conditions for a while. The sparsity actually helps keep you in the here and now of the story, which is important from a writing standpoint.
I also think we've been underestimating how devastated the mob was by the end of TDK. I always felt the only way the mob was coming back in a third movie was if they came back under the leadership of freaks (like Black Mask) and completely changed their game, became more unpredictable, ruthless, etc. It seemed certain that an inability to evolve would render them extinct in Gotham. Joker himself told them they were on their way out as he burned their cash. I understand that there's a thematic way to interpret his line about giving Gotham a "better class of criminal", and that it might allude to the rise of freaks, Batman's rogues gallery, etc. But in a literal sense he's also talking about taking over the Chechen's gang. Joker was right almost all the time in the movie, but he wasn't totally infallible. He was wrong about the ferries, he hadn't planned to get caught so soon and he couldn't foresee Batman taking the fall for Harvey, which is the moment that altered the course of the story going forward. It was Batman's ace in the hole.
I will say...I do understand where the other side of the argument is coming from. Something like this bothered me in Iron Man 2. I wasn't a fan of Tony's blood being poisoned and him dying at the start of the movie. It didn't feel natural coming off the high note the first film ended on, seemed to come out of nowhere. Looking back though, I think I would have been able to get over that if I found that particular subplot led anywhere useful. Instead, it just felt like an excuse to throw in a "dark" but disjointed subplot with Tony curing himself that crammed in a bunch of Avengers setup and was not essential to the rest of the story. So I do get it. You feel like you had the rug pulled out from under you and got a different story than the one you felt should have been told. At the end of the day that's all it comes down to I think. All the disagreements that have played out on the boards, from the merits of the Dent Act, to Bane and the LOS's motivation for coming to Gotham, to Talia's role in the story, all consistently point to this conclusion. If you changed all those things you'd have a radically different movie. A better movie? I couldn't possibly say.