The biggest stretch came with Two-Face in that the severe burns Harvey suffered from didn't cause him to succumb to sepsis or die from extreme pain pretty quickly. (And let us assume Harvery Dent could still be alive and in Arkham in the Nolan verse and able to live with his injuries.)
Well, I don't know if I agree with that assumption. I think part of the reason Harvey went on a revenge kick in
The Dark Knight was that he knew he only had a little while left to live. But I digress.
Could Mr. Freeze be done and still keep the realistic tone of the movies?
Maybe. They probably would have to tone down the extreme temperature differences and would need to cut the sci-fi freeze ray gun bit, but the emotional core of the character as re-interpreted in
Batman: The Animated Series might be enough to carry his arc. Certainly the Nolanverse has skirted on the edge of realism before.
I think The Penguin could've worked the best and have undone the bullshit caused by the butchering Tim Burton did. The Penguin could've been portrayed as nothing more than a old-timely dapper, odd-looking, mob boss.
I absolutely agree that the Penguin could work that way in the Nolanverse. But the problem would essentially be that it would feel repetitive; the Penguin would just end up feeling like a gimmicky mafia boss, but one who plays up to English stereotypes instead of Italian stereotypes. He'd just end up being a posh, ethnically English version of Carmine Falcone.
I think Poison Ivy would have worked very well, as an eco-terrorist though she'd probably need to be paired with someone else to best work unless a big enough plot could be made around just her.
Hm. I mean, she could work, maybe, as a non-superpowered eco-terrorist. But they'd probably need to cut her superpowers entirely -- which I think would hurt the character, frankly, because the essence of Poison Ivy is the dichotomy between her sexuality and her physical alienation from other people. She plays into the archetype of the Temptress or Succubus, and without those superpowers, the character loses a lot of its emotional power.
The Riddler would work pretty well as a demented serial killer teasing Batman with clues and in itself could "undo" what Carry brought to the role in BF.
Well, Jim Carrey in
Batman Forever was essentially just playing a hyped-up, Carrey-fied version of Frank Gorshin's Riddler from the Adam West
Batman TV series. So I don't think it's fair to just attribute that to Carrey.
The Riddler might be the most promising supervillain in a hypothetical future Nolanverse film. A darker, more intellectual serial killer, as you imply, or perhaps a political terrorist. (Nolan loves using Batman villains to ask challenging questions about the health of American politics, after all.) Something like a slightly Batmanified
Se7en, perhaps.
To each his own, but I don't see how Burton's Penguin could appeal to anyone at all.
Well, I love Danny DeVito's Penguin as much as Burgess Meredith's. It helps that my mother brought me to see
Batman Returns when I was 6 years old, and thus I didn't have any preconceptions about what the character "should" be.
David Tennant for the Riddler.
Ooooh. I really like this idea. I was thinking Benedict Cumberbatch, but Tennant is better.
As for other options...
For supervillains, Black Mask, Hugo Strange, and Hush all come to mind.
With reservations, Harley Quinn, the Mad Hatter, and Mr. Zsasz are also options. It would probably be a bad idea to do Harley without bringing back the Joker; it would just feel like a re-tread.
The Mad Hatter might be a little bit too fantastic in his modus operandi, though it would present an interesting opportunity to explore the boundaries of sexuality, power, and rape in a crime fiction context. That might be too dark for a film that still has to be able to be accessible for children even when its primary audience is adults, though.
They've already touched on Mr. Zsasz in
Batman Begins, but there's no reason I'm aware of that he couldn't be one of the Arkham escapees let loose upon the Narrows in the finale of the first film.
Holiday came to mind at first, but it occurs to me that the general political development that Holiday heralds in
Batman: The Long Halloween -- the fall of Gotham's organized crime families and the rise of the fantastic supervillains -- has already been accomplished in the Nolanverse's
The Dark Knight by the Joker.
For general organized crime antagonists, there's still Lew Moxon, Rupert Thorne, and Tony Zucco. They'd probably need to be supporting roles, though, since the Gotham mafia families have been drastically reduced in power as of
Dark Knight.
Random thought: I always wondered why we never saw Harvey Bullock in
The Dark Knight. Keith Szarabajka's Detective Gerard Stephens (the one the Joker tricks into beating him and then takes hostage to get out of lockup) certainly plays on some of the same visual archetypes that Bullock plays into. But I digress.