imagine this:

angelina jolie as talia, daughter of ra's al ghul, out for revenge with the league of assassins. you could even, if you wanted to, incorporate the lazarus pit (on 2nd thought, nolan wouldn't do that i don't think), and bring back liam as ra's (though i would still have talia be the main villain). while trying to kill batman, talia falls in love with him. maybe in the same film, you could introduce selena kyle (i think someone here said charlize theron, or my personal favorite, scarlett johanson). selena and bruce fall for each other, which is why batman doesn't go completely for talia, and ends up having to stop her plan, though she can't hate him because she loves him and everything about him so much. this could set up catwoman if there is a 4th film.

shit, have the 4th film be about knightfall, but done right. break out all the lunatics from arkham. even though she's a thief, catwoman sees the wear on batman as he fight's and apprehends all these lunatics (maybe a few could get away, like the joker...), so she starts helping him, which begins a little partnership. then we find out bane is behind it. he and batman fight, and he gets the better of batman, but before he can seriously hurt him, catwoman somehow intervenes...ok, that's all i got..i don't know...lol