Joker without a sense of humor isn't the Joker. That's the defining characteristic that separated him from all the cookie-cutter cliché killers that are a dime-a-dozen in comic books. There’s nothing inherently unique or intelligent about a murderous antagonist. He's made unique not by being a killer, but by how he kills with a sadistic sense of pleasure and humor. Homicide made fun. His humor's required. He's being treated perhaps too dark anymore. It's getting so hyper reality that it's ironically becoming just the opposite; unrealistic. I like the prankster/killer blending and that’s certainly the most ironic and long-lasting version of the character. I’d classify that Joker as Killing Joke Joker though; Basically BTAS Joker without restrictions or even Jack Nicholson. Heath even played him on levels, just less gimmicky. I really don't think many of your example Jokers are all that different. Prankster Joker has been Heath Ledger in ways, he’s been gang lord-like at times, he’s been horrifyingly frightening. You picked poor examples. No offence. Your three oftentimes blend together in the comics and films. The vastly differing Joker interpretations through the vast history of Batman lore are generally considered by comic historians as;
- Original Bob Kane/Bill Finger homicidal murderer: In the 1940’s he essentially was a straight-up homicidal maniac with little sense of humor. This was extremely short lived as he increasingly got more and more sickly comedic as his appearances went, so much as morbidly laughing at the irony of being stabbed by his own knife and the notion of his own death.
- 1950's Comic Code Joker: Extremely censored and more mischievous then ever deadly. Not really threatening whatsoever. Think Cesar Romero.
- 1970's Dennis O’Neil revival: He took the Jokers roots and meshed them with a skewed, twisted, and dark version of the comedic side, blended them together, and out came arguably the most iconic version. This essentially encompasses Killing Joke, Jack Nicholson, Batman the Animated Series, and Heath Ledger Jokers to varying degrees. Some have a pinch more Original Joker, some a slice more comedic, but they all belong in the blending catagory.
You could argue that Mark Hamill’s animated interpretation wasn’t nearly as fierce, but I’d argue that it’s not out of a lack of trying but merely that Batman stops him before he can do it, nor does graphic and gratuitous violence make the character what he is. Admittedly they couldn’t get away with showing murder fully on screen, but they did show his gassed and grimacing victims. Bruce Timm feels that, in some ways, that’s worse. He’s every bit as deadly…just fought a losing battle against an animated “children’s show” timeslot. I use that term loosely as that show was anything but a Saturday morning cartoon. It had an unprecedented amount of adult undertones that never ceases to astonish me. They got away with everything but murder…and even then you know it’s going on behind the curtain.