With the "classic" Bat-villains, to me it seems that whenever they DO attempt to modify them, they're soon back to their old appearance when the next creative crew comes on-board.
There was an attempt to make Riddler a Joker-esque psycho in the mid-80s, but fans whined about "classic" Riddler. Mr. Freeze and Killer Moth were given overhauls in the mid-90's, but they didn't last. Freeze's was exceptionally weird. He appeared in "Green Lantern" looking like Iceman and having similar powers. A month later he was in the Batman books with his armor-plated look and displaying none of those powers.
Penguin would work as a Kingpin type, but fans (or more likely it's the creative team), seem to end up back at the tubby guy with the big nose who uses umbrellas. In the 90's and even during "No Man's Land", Penguin was kinda' the Kingpin of Gotham...but they reverted him. Several times. I remember a Kelley Jones/Doug Moench issue, circa 1997, where Penguin just said "f this" and decided to go back to smacking Batman with an umbrella.
Also, his flippers and sharp teeth seemed to come and go at the artist's discretion. That seems to be a polarizing point to Batman fans: no flippers or flippers.
I wouldn't say "revamp", but some Bat-villains I'd like to see get more focus and prominence are Firefly, Lock-up, and the Ventriloquist/Scarface. Yes, those are all primarily from the 90's and I'm playing favorites. Ventriloquist is probably my favorite Bat-villain.
Lock-up was interesting, because he received a lot of hype and fan acclaim when he debuted in 1996. After that, I think his only other appearances were in "No Man's Land", when he was the warden of Blackgate (or was that KGBeast? I forget).
One villain I would like to never see again is Two-Face. I know, I know... his whole duality gimmick is incredibly tempting for a writer. But I've never cared for the guy in any incarnation. He'll always seem like a reject from Dick Tracy to me.
One thing I'm really enjoying right now is the MIA status of Joker. He's way overexposed and I'd like to see them go a couple years before his big return to New 52 land. Two Face is another that is heavily overexposed. Seems like every writer wants to come in, do a Joker story, do a Two Face story, and leave. And most of the writers don't understand how to write him anyway, they always forget the good side of the coin.
I'd love to see a modernizing/redux of KGBeast, but, then, "Ten Nights of the Beast" is one of my favorite Bat-stories ever.
Mr. Zsasz (I, too, am a child of the nineties) could be re-made in a more interesting fashion. While there's always been psychosis in the Bat-Gallery, Zsasz was the most fitting into the serial killer archetype (again, probably a weakness as I love "The Last Arkham", which I think was his first appearance). But after that first story, he just became kind of generic and knifey-slashey, with no real intrigue (admittedly, I'm out of the loop on a lot of recent years, so forgive me if I'm wrong).
"Never piss off a hawk with a blowgun" - Conan O'Brien
KGB was good for that one story, but he doesn't work as a reoccuring villain IMO.
Most of these characters are handled extremely well in the Arkham City game. You get a classic serial killer Zsasz, badass Penguin, etc... About the only misstep is their Deadshot, who foregoes the classic costume for something a lot more generic.
No disagreement about any of this. I knew one day we'd be faced with Pratchett "hanging it up" so to speak, but I certainly had hoped he'd have a chance to ride off into the sunset and enjoy himself a little.