That's true, but unless they develop an entirely new villain specifically for the movie, they don't have a lot to work with. Penguin, Mr. Freeze, Poison Ivy, etc are all fairly minor bad guys. Harley Quinn is nothing without Joker and to a lesser extent Ivy. Catwoman and Riddler, while decent villains in and over themselves, they do not do much of anything spectacular and they both become "good guys" in a general sense. Despite Nolan saying he wanted something different from everything else done on Batman, he cannot exactly ignore Batman lore and fact without disrupting half of whatever fandom he has created for himself and his movies.
From what I know, Bale and the rest of the cast have signed on to make three complete movies. Although this doesn't mean they will not develop more with the new cast if the third movie does just as well as the second one has been doing.
It would probably serve as a cushioning but not much more than that due to it being light weight and enabling him better movement.I'd imagine it would be resilient enough to prevent things such as snapped spines and other such things which cause death from falls.