Here are some possibilities that I wouldn't mind seeing based on that list of actresses and the characters they could play.
- Natalie Portman - Harley Quinn (villain). Revenge storyline to follow up on the Joker plot from TDK.
- Naomi Watts - Poison Ivy (villain). After the way they handled Scarecrow in the first film, I think they could find a plot that wasn't derivative (or only slightly) and create a good bad guy with this character.
- Rachel Weisz - Selina Kyle/Catwoman (love interest/foil). Love interest for this film, intro Catwoman and maybe set her up for a possible fourth film?
- Keira Knightley - Talia al Ghul (villain/love interest). Another revenge storyline with some potential.
- Ann Hathaway - Vicki Vale (love interest) would have to go along with a villain, maybe either Poison Ivy or Quinn.
- Blake Lively - Don't want to see her in this film, she's already dropping into the DC universe in the GL film.
My favorite choices would be Portman as the villain, Quinn, and Weisz as Kyle/Catwoman, the love interest for the film who could also cause some additional frustration for Batman.
If not, I'd go for Knightley as Talia to play both the love interest and villain.
Either storyline would have some been there, done that stuff with it but I think Quinn/Kyle would make a helluva film.
I'm not an Ann Hathaway fan and really would have no interest in seeing her in the film in any role. I also wouldn't like seeing Lively here as she's already in GL. Portman is in Thor so seeing her in yet another superhero film could be a little redundant, so I'd have no problem with Knightley as Quinn if Nolan went that route for a villain.