Bane is basically a setup of a character that gets lost in his own loop hole. He really had no plan, other than do whatever Talia wanted; and that called for escaping from the Pit with Talia and being trained to become a member of the LOS. Later on, when Ra's gets an idea that he's a bit of a rage monster with zero control and banishes him from the League.
Meanwhile, I guess
Bane does practically nothing between his banishment and the events following after Batman Begins until Talia finds out her father dies and calls upon Bane to be a mysterious plot device for her plan. The movie implies that Bane's only real motivation is doing whatever Talia wants, but I like to think he was doing as he pleased too. It's safe to guess from being in the Pit for so long for reasons that could be similar to Vengeance of Bane, his view is of a prison world. And with that, he sees Gotham as an even greater prison and Batman the warden: logically, his mindset tells him to break the Batman, and from that he becomes the top dog.
But at the same time, it doesn't make much sense, does it? Why would he want to rule Gotham only to be working under Talia for her love? Not to mention if Gotham were to become his and become another Pit of Despair, if you will, why create a temporary prison to blow up? There's no real follow up, and you would figure he would be aiming for a greater evil that would be a bit more permanent. LOL
And how it sounds on Talia's end, she sounds like yet another stupid woman we know of that has daddy problems. I can't blame her though! All of her life she grew up in a prison with her mom only to see her be killed. Dad's not around because the War Lord found Ra's marrying her daughter behind his back. For that, he sends his own pregnant daughter into a raging hell and makes Ra's an outcast.
That part makes perfect sense.
Later on in the Pit, she befriends Bane; she's found a big best friend that protects her and he has his own little Osito. Basically it's a romance between Chewie and a female Han Solo, minus how pedophile-ish it may seem. But then again, I can guess at this point when Talia escapes, she's between 8-10 years old, and Bane is probably 16 at the time.
On that side of the world, that makes sense.
When she escapes and Bane helps her in the process, being brutally beaten in the process, it's probably shortly after Talia finds her father (who's already begun creating the LOS) and they go into the Pit to save Bane. I'm surprised it took Ra's that long to go out save his own daughter, but at the time he probably didn't know he knocked up his wife before sending her to her death. I won't be picky and question that to no end. ANY WAY. He finds out he has a daughter. To make up for all the years that he never had with Talia, being the irresponsible father he was, goes over and saves her boyfriend from the pit. Ra's probably thinks "hey, he seems like a nice guy: takes care of Talia when his wife killed, gets beat to hell so she can escape. What the hell!" Ra's, Talia, and the League finally go barging into the Pit to extract vengeance on everyone there and save Bane. What could go wrong with this fantasy of a morbid fairy tale ending?
With some consideration Ra's takes in Talia and Bane, trains them to be members from the LOS. You never see Talia use this hand to hand combat and skilled ninjitsu, but other than that... once again, it's a rational train of thought.
After awhile, Ra's sees that Bane has anger management issues and has probably gone through 40 different members of the League like toilet paper, and decides enough is enough! Pulls his thoughts together, gives Bane a slap on the wrist and excommunicates him from the League because he's a reminder of his wife and the hell he stuck her in... and that he probably hulked out too much when he shouldn't have and killed about 42% of the group he invested years in making. He DID take the time to get his newly formed order to save his @$$ from the Pit. And in return, kills almost half of them, or safe to assume that he does. What other kind of reckless behavior would you expect from a group of deadly assassins that would make Ra's a little ticked off? In the eyes of Ra's, Bane is a reckless hummer driving douce bag monster and doesn't deem him fit for his daughter.
If I was a father and just found this out about a daughter I never knew that I had, I would kind of feel the same way.
With Bane gone, I guess Talia has a b*tch fit and never speaks to her father again. So for years on out, she then ONLY decides to forgive her father after he's dead. Talia's pissed because she's under the impression that Ra's only excommunicated Bane because he loved her. It could VERY WELL be the case, but again... I won't question it.
So Talia leaves because she's pissed with daddy for taking Bane away. She never speaks to him or comes around to forgiving him until she finds out Batman murders him... which, let's be honest, DID. LOL
And because Ra's failed to cleanse the world with an Ozymandias like motive (that has its benefits in an overly extreme way), Batman within 8 years is able to purify Gotham for the most part with the help of Dent and Gordon... without killing anyone. Minus Ra's, who he left on a train with no rail and a device that could explode at any time. And Harvey Dent... because he got butter fingers and dropped him accidentally after shoving him off of 6-10 story roof only moments earlier. It was a lie, sure, but most great things come from secret lies.
So in a nutshell:
-Talia in a angry PMS fury, devises a plan to destroy a Gotham that's already been, for the most part, saved, with the help of Bane whom considers only a friend at this point after fooling around with Bruce.
-Bane is friend zoned and does everything in the name of Talia's love while attempting to have his own fun along the way. Which includes breaking Batman, putting him in the Pit that he endured for years for reasons we can assume that was created by Chuck Dixon.
-The Emperor Palpatine of the story, Talia, makes a half-@$$ed plan as an apology to her father who shouldn't have been fooling around with his bosses' daughter in the first place, and in the process marrying her as an apology for not wearing or breaking his condom.
-And from there, Talia takes advantage of Bane's love and makes him do all the hard work as a grand master dictator... While she dolls up for a board member job in Wayne Enterprises, only to throw parties and screw Bruce Wayne on the side because she's a typical artificial b*tch.
THAT'S where the tires fall off for me.