Skipping back to good guys for a bit, since I'm still running out of villains, let's talk Dr. Leslie Thompkins. Just as Alfred Pennyworth has been a father figure to Bruce Wayne, Leslie has traditionally been like a mother to Bruce. A friend and colleague of Dr. Thomas Wayne, she took an active role in helping to raise Bruce after his parents' murder. In some versions of the Batman origin story, Leslie is among the first to arrive at the scene of the murder.
Leslie eventually learns that Bruce has become Batman to fight crime in Gotham, but unlike Alfred, she does not approve. As a pacifist, she believes that Batman's vigilantism will only lead to more violence. Though she tolerates him and occasionally provides medical help, she takes every opportunity to try to talk him into hanging up the cape and cowl. Her most radical attempt was during War Games, when Black Mask tortured Spoiler nearly to death, Batman brought her to Leslie. Leslie allowed her to die, hoping her death would convince him to end his crusade against crime. Much later, it was revealed that she had only faked Spoiler's death, and that Batman had suspected as much, but their relationship seems to still be strained.
Pros: Although a few people have learned that Bruce is Batman, everyone seems to agree with his way of thinking. It would be nice to see someone challenge his reasoning and really try to convince him to stop.
Cons: She's a relatively late (1976) addition to the Batman mythology and it might not work to cram her back into the origin story with new flashbacks. Alfred seems to work fine as a single parent figure, so there's no real need for a "mother."
How I'd do it: I suppose you could skip any flashbacks, and just have Batman injured. Unable to summon the Batmobile and too wounded to make it back to the cave (or the basement thing, if he still hasn't moved back to Wayne Manor), he realizes he's near a free clinic run by an old friend. He stumbles into Leslie's office, she's briefly startled but he takes off his mask, and naturally she tends to his injuries, but when he wakes up the next day she scolds him for being reckless and ignoring everything she'd ever taught him about violence. That's basically how half of Leslie Thompkins' appearances in the comics have gone, but it's a formula that works, I think.
Casting Guesses:Diana Muldaur (Dr. Pulaski from Star Trek: The Next Generation) voiced Dr. Thompkins in the Batman animated series from the 1990s, and did a fine job, but it looks like she may have retired from acting. Most of these types of parts go to Judi Dench or Hellen Mirren, but I'd like to think there's someone else perfectly capable of it. Ellen Burstyn maybe?
Verdict: A definite possiblity. Considerably more likely that any of the Robins, at least.
After The Scarecrow, Ra's Al Ghul, The Joker, and Two-Face, who should be Batman's next enemy in the Batman Begins/The Dark Knight series? Well, as of now we know that Tom Hardy will play Bane and Anne Hathaway will play Catwoman.
Check out the master list for all the villains covered. I've pretty much run out by now. Obviously, there are more Batman villains, but not any of significance that I know of. As of February 2009, no one is confirmed as a villain. Not the Johnny Depp Riddler, not Phillip Seymour Hoffman Penguin, nobody.