You know alot of people are saying it isn't dark enough, I gotta ask how you come to this conclusion? It's a freakin' 1 minute trailer, you can't even come close to gauging what the final product will be. I don't even think they've completed principal shooting yet, we should be glad we even have the 1 minute trailer.
Also, you have to take into account that to sell the movie you can't make it as dark as the comics, even though I agree that'd be awesome, 90% of the movie-going public doesn't read Batman comics. If they make the film too dark, it won't sell, people in general won't understand the the dark overtones and people are usually fearful of things they don't understand.