I think this can be said of a fair number of Nolan films (let's throw Memento and The Prestige on the pile for starters). He's got more sympathy for ideas and puzzles then wringing tears from the audience. Which is alright for me, none of the Batman films have been affecting emotionally and doubt that'd change. The staticity of the superhero scenario is part of the problem - The Dark Knight can only kill lower rung good guys, and Rachel Dawes is so dispensable as to make her very death irrelevant.
Insomnia doesn't seem to come up much in discussions of Dark Knight. But the action in that movie is supposed to be driven by fear that discrediting Al Pacino's cop will lead to the release of criminals. So Al Pacino gives up his life to preserve justice/his image simultaneously, while Hilary Swank looks on in shock. In Dark Knight, the success of the Rico prosecution hinges on Dent's image, motivating Batman's "sacrifice," while Gordon looks on in grief. I liked Insomnia better. The only ambiguity was about Pacino's motives. If you somehow believe that society is an illusion held together by mutally agreed upon symbolism, I suppose the hysterics about Dent's image wouldn't seem so absurd. I don't understand how anyone can be so confused about the world, though. It's like thinking that the Joker's nihilism is a real philosophy or a real mental illness or a real anything.
I think it was more that if Dent's image was "tarnished" a number of things would happen including him being dis-barred (thus meaning he couldn't prosecute for the RICO case), someone else would step-up as DA and that person may be better influenced by the crime in the city to get the RICO case lost/thrown out. They needed Dent because he was a clean, good, lawyer who wanted to solve the city's problems and they may not get that with another DA. His image being tarnished by his involvement in crime would really mess things up in prosecuting the criminals. So I saw it as being less about his image and just more about the politics and practicality of the whole legal system.
Well, one of the major issues of suspension of disbelief in viewing the movie is buying the whole "DA manages to prosecute hundreds of mobsters in one case" conceit - that's pretty far-fetched for a police procedural story, which is the style The Dark Knight mimics, though it's not at all out there for a superhero story. The basic premise of the Nolan Batman movies is that the symbolism of powerful people is critical in the life of Gotham City - it is the hinge upon which Bruce's entire conception of Batman turns in Batman Begins. Carrying that forward into the story told in the Dark Knight is extremely thematically consistent. However, if you can't buy that premise then the movies aren't going to work for you at all.
Well, the mobsters were pretty foolish in not diversifying their money and, instead, keeping it all in one banking system thus making them all connected should a RICO case ever come up.
I loved the movie until the very end - I was somewhat pissed off coming out of the theatre and I couldnt quite describe why until some time later. The movie ended. Or rather, it ended 5 seconds too soon. I wanted the big rise in the music to carry on and Batman to shoot out of the tunnels into the gotham night, but that never happened. So to this day, I love the movie but that ending just pisses me off on a subconscious level which boils its way up. I know its a stupid thing to dislike and ruin the movie, but I just think the rest of it is so perfect, I wanted to relish in Batman's sacrifice, I get why it cuts short, and to an extent I agree with it, but it just riles something inside of me for some unexplainable reason. Still one of the best movies in recent memory though and further solidified why Nolan is one of the best filmmakers of our time.