Bane was not a henchman, and Talia al Ghul doesn't take away from him but adds to him. They were collaborators in their plan to make an example out of then destroy Gotham City. Bane was a leader and badass in his own right, he was never "friendzoned". Their dynamic is also based on Monsieur and Madame Defarge, the villains from the classic book A Tale of Two Cities which inspired the movie.