Re: Why did the League of Shadows want to destroy a peaceful city?
The League is described as watching society grow and striking when they see it becoming decadent. This suggests there is a measure of moral judgment they make based on the condition of the city, which is ever-changing. They're watching closely, they have some degree of hope that it won't go bad, or they wouldn't allow it to exist for years in the first place.
So that's why I'm not as black and white on Ra's or the League. They're not strictly evil even if their methods are wrong. Terrorism comes in many shapes. Look at V.
In regard to whether or not they would still be causing the problem when exposing the truth about Dent, the problem would have already been there, they would simply be administering what they thought was the cure (and of course Bruce and you and I would disagree).
But why I find this compelling is that it wouldn't be necessary to mislead or manipulate people into being corrupt, and that would make it tougher to call them wrong about Gotham's corruption. They don't have to fake a reason to strike (other than mere revenge), their motivation will be legitimate from the get-go. They would at least have an argument to make. I don't like that that argument boils down to a fist-fight with no philosophical conclusion, however, so I would amend that too.
About his parents, I also enjoyed that, but it would have been more powerful if they were relevant throughout. A gravesite visit after Bruce gets back to Gotham would have been a great rekindling moment, like saying (or silently implying), 'I'm back, and I won't let you down again'. Bruce fell and learned to pick himself up, completes the climbing out of the pit ordeal to perfection, and then later that promise he makes at their graves is tied off nicely with the Wayne Orphanage and the graves including his at the end.
Bang, tears jerked instead of tickled. For me, anyway.
I think maybe we just wanted different movies. Along with the idea I threw together above, I wanted a stronger motivation for both Bane and Bruce, and I wanted certain characters and concepts fleshed out more (and some maybe trimmed down or even scrapped). The development felt incomplete to me.
Hell, this could even have been a two-parter.
Why do we fall?