I think Selina Kyle would be a great addition to the Bale Era. Bruce needs a new love interest, movie series needs a new villain; that's two birds with one stone.
And call me crazy, but imagine one of the bat-posers actually being damn good. Good enough to give Bruce a run for his money.
I also nominate Jean Paul Valley (Nightfall Batman) for the next Bale Era villain. Hell, we could call the movie Knightfall. I'd do it like this:
Now that Batman is a "Killer", this inspires Valley to get extreme himself. But when he learns Batman really isn't as hardcore as he heard (maybe he sees Bruce letting a certain Catwoman slide?), he appoints himself as the Batman the city requires.
That would work for me.