Re: The ferry should have blown up
I completely agree with you. I think that the ferry scene was the most unrealistic part of TDK, in the sense that it is highly unlikely that what happened in the film would have happened in real life in a similar scenario. There actually have been incidents in history that show the exact opposite of what TDK ended up doing in that scene.
Not only would I have had the "innocents" blow up the criminals, but then I would have had the Joker blow up the ferry with the criminals right after that. The look on Batman's face in such a situation would have been priceless.
But at the end of the day, all of this would have been way too dark. If they had gone that route, TDK probably would have been one of the most depressing, nihilistic films ever made and would've caused a lot of controversy.