Re: Why did the League of Shadows want to destroy a peaceful city?
I think OP is right. That this is one big drawback to the film. It can be explained by saying the LoS is a radical group, quite obviously villainous, and that they needed to be taken out because they had no rationality behind their actions. Which does an okay job at making the film respectable, but in no way makes half the villains in the franchise sympathetic or relatable. Instead it makes them seem purely like psychopaths (which it could be argued Batman's villains should be). So anyway, that along with Batman's retirement, Joker's absence and the anticlimax in general, made this the weakest installment of the three in my opinion.
I just stole a poncho from a wooden Indian...