yyahoo: Heath played the Joker as he was written for that particular take on the Batman universe. I don't think that the Joker that you're talking about would have worked well in Nolan's version of Batman.
Stevedog13: I agree to your point about how he was written. I think Nolan took the easy way out by making the Joker more subdued and brooding. Nicholsons Joker was too hammy and over acted, which would not have worked in the Dark Knight setting. But it was more Joker-y.
For what it's worth my favorite Joker movie was The Mask of the Phantasm. Yeah I know it was an already established character portrayal, but I went to see it in the theatre so it counts. There is a scene I absolutley love where an aging Mob boss turns to the Joker for protection from the Batman, who has supposedly gone crazy and started killing crime lords. He grabs the Jokers lapels and says "Please, you gotta help me." The Joker then gets very, very angry, growls, twists his lips and shoves the guy back against the wall. He screams "Don't Touch Me!" then instantly regains his composure and say very nonchalantly, almost jokingly, "I don't know where you've been" and walks away giggling at his own humor. This too me was a perfectly Joker way of doing something. The closest that Ledger-Joker got to this level was "Very poor choice of words." From what I understand the Arkham Asylum/City Joker is basically the same animated Joker but much darker.
Oh, yes, Mark Hamill (as a voice actor) was the very best Joker, IMHO, and better than even Heath's Oscar winning performance. It's still difficult for me to imagine Luke Skywalker as the perfect Joker, but that's the wonder of voice acting, when it's done right, you don't even think about who the voice actually is in real life. It's also why I hate stunt casting for animated films so much. I don't want to think about how that's Brad Pitt or Owen Wilson or whoever's voice, I want to get lost in the character and only a voice-over pro can pull that off, but I digress.
Affleck just doesn't have the range necessary to play a character with a "dual" personality. I don't think his Daredevil was wooden because he believed that a blind person should be that way (and truly, when you think about blind performers, are they really all that wooden in their facial expressions? Stevie Wonder? Ray Charles? Usually it's the opposite, they overcompensate). I think that's just all he had to give. Kind of like Keanu Reeves or Kevin Costner, when a part is written for what they do well, then they can succeed, but never give them anything that will force them into a position to stretch their skills, because they'll just give you the same thing they always do. Affleck has acted well in a few movies, but those were parts well tuned to his best performance. Batman is not one of those parts.
I wonder if this information was "leaked" just to get a public response to the idea and if a negative outcry is strong enough then Affleck might suddenly find his schedule too otherwise too full to participate...