The Riddler is supposed to be a fairly composed sort of fellow, very droll, very witty, but in an acerbic sort of way. Carrey just made him into a loon.
Mr. Freeze is supposed to be a little subdued, and very sad. Arnie just made him look like a deranged mini hulk.
Poison Ivy admittedly is a big bitch so her character wasn't portrayed so bad in Batman & Robin. She's supposed to be really in love with plants, but she's not superhuman and she can't like, force them to do whatever she wants. She just has some tricks up her sleeve with a floral theme.
Bane is really awesome but IMO I think he was destroyed too thoroughly in Batman & Robin. Everyone knows him best as being a big hulking brainless zombie sort of thing so that'd be hard to pull of making him a main villain.
I'd L-O-V-E for them to do Clayface, I always thought he was so bitchin. He was one of the few Batman villains that actually had "superpowers". He wasn't even particularly deranged, outside of his hatred for the people who made him a freak, and the hatred for himself.
I'd also l-o-v-e to see Ra's and some Lazarus Pit action, but I doubt that'll happen.
I wish they'd shown Harley Quinn, though, she was always my favorite Batman character for some reason. I think mostly because she was just a normal woman with daddy issues so bad she kept running back to the maniacal Joker. No chance that'll happen in the future, now, thanks to good ole Ambien
Anyway, I love Batman villains. Batman himself barely speaks, and is very cut and dry, but the villains make him special, because they're all so fucking crazy in their own, very dark ways. I hope they keep up this momentum with these movies; they're doing an excellent job.