Re: In hindsight what changes would you do
Bane never seemed to me like he was just Talia's love-sick lackey. Of course he would be the one to stay behind and guard Batman while Talia ensured that the bomb would explode. Batman could easily take down Talia if she were to be the one to stay behind.
Bane showed little regard for following Talia's orders and throughout the film seemed more like a protective father figure than a starstruck lover. He's much older than Talia, helps her escape after her mother is killed, and then continues to look after her later. Ra's feels jealousy because HE is Talia's father but she shows her affection to Bane, the man who took care of her and saved her. So Bane is driven to be a better leader of the League of Shadows than Ra's ever was, and Talia is driven to avenge her blood relative's death.
At no point does it appear that Talia is giving orders, as she is largely undercover for extended periods of time. Meanwhile, the entire league follows Bane's orders with palpable fear and unquestioning loyalty. Talia never got an extended finale because she wasn't the main villain of the film. In the end she was just the twist reveal and the driver of the bomb car. That's a disappointing use of a comic character but it doesn't make Bane just a goon.