The twist of revealing Miranda as Ra's daughter might make sense as according to canon/mythos (I've updated my Batman knowledge today via wiki
), but you could argue that it wouldn't have made any difference if it had been Bane driving the bomb truck instead of her.
So why include the twist - it comes over as service to the fans instead of service to the story. Yeah, the Scarecrow cameo made little sense but then again, I wasn't aware that the character has ties to the League. Ra's cameo was cool, even as a phantasm inside Bruces own mind projecting his inner thoughts. I'd somehow wish he hadn't died in Begins, so he could be utilized in this film and that could have been the major twist instead. Batman was robbed of a final showdown with the Joker because Heath died after the shoot - Bats/Bruce really needed a showdown with a villain that had made a huge impact on his life prior to this film. Ra's fits the bill to me...
PS: not trying to put down the film or your/other posters opinions. I just think I've watched the first Nolan film since the Pacino thriller remake, where I'm left with the feeling that he's not
entirely invested in the project...