Re: In hindsight what changes would you do
That's assuming they knew her name was Talia i guess, maybe they did but didn't mention it because they feared Bane? Even so, the point of the reveal wasn't really that it was in fact a girl who was the child. Bruce was already under the impression that the child of Ra's was destroying Gotham, who he believed to be Bane. Finding out it was a girl, maybe eventually, doesn't change the fact that it was still the child of Ra's.
The key to the reveal is that it was actually Miranda, the woman he liked (maybe?), gave control to his company, and slept with. Sure, he maybe would have eventually figured out it was Miranda (if he wasn't dead yet), but even when she does reveal herself to be Talia Bruce looks so shocked that he can't even believe it.
Maybe Talia really didn't care to reveal herself to Bruce, maybe she did sleep with him just so she could try to convince him to come with her shortly after to take him to the pit herself? Maybe just knowing Bruce failed and she would kill Gotham was enough.