I think that thing with the Robin reveal at the end is being taken far too seriously. To me, that's just a little nod, like a joke from Nolan. It's mentioned and then quickly disposed with "Hey you should change your name to Robin!!" "Ah yeh whatever."
I thought the character fitted in well. For the whole movie, he is pretty much Robin. Just not in costume. And to me that plays so much stronger to what that movie is all about, with the rise against Bane and the others. Because all Bruce Wayne wanted, as he said in the first movie and even reflects in this one, was that he wanted to inspire people and wanted to say that anyone could be Batman. And so here then in this movie you have this regular guy, who's even less fortunate than Bruce was, being inspired by Batman and just being good to people, providing hope when there wasn't any, and just looking out for his fellow man. He goes as far as Batman without being in costume and I think that couldn't have been handled better to close that aspect of the trilogy in all honesty.
Is it the best movie ever? No. Is it the best of the trilogy. No. But is it a good action blockbuster? Absolutely.