Question: How exactly did Bane's mask work? Was he breathing some form of gas? Where was the gas stored? I didn't see any pipes leading into his back or anywhere on his body.
Not to mention a blatantly obvious point of weakness that Batman would have taken two seconds to attempt to tear off or damage first encounter. He has gauntlets that could have torn it up I would say, he was able to connect punches so it's not like Bane was protecting it well.
But that's movies for ya, especially so in comic movies.