^I strongly disagree. Hamill's Joker was a fantastic performance in its own right and would be even if you had no idea that Hamill had played any previous famous character. He brought a lot of range and versatility to it, and was effective at conveying both the funny and scary sides of the Joker.
And really, what's wrong with the Joker being broad? That's kinda the whole point of the character, that he's insanely flamboyant and larger than life, that he puts on this farcical, clownish show while underneath it is a shocking brutality and sadism. And it works as a striking contrast to Batman's grim reserve. The more downplayed incarnations of the Joker -- Heath Ledger in The Dark Knight
, John DiMaggio in Under the Red Hood
, Brent Spiner in a recent Young Justice
episode -- are the exceptions to the way the character's usually played. Most Jokers -- Cesar Romero, Jack Nicholson, Mark Hamill, Kevin Michael Richardson (The Batman
), Jeff Bennett (Batman: The Brave and the Bold
) -- have been broad and over-the-top.
By the way, ComicsAlliance reviewers Chris Sims and David Uzumeri made an interesting point about Hamill's Joker in some of their recent columns reviewing Batman movies: that the performance it's most inspired by is Frank Gorshin as the Riddler from the '66 Batman
sitcom. Gorshin's Riddler had that same ability to go from sheer zaniness to growling menace in the blink of an eye. And Hamill's Joker has a similar cadence and delivery to Gorshin's Riddler a lot of the time, not to mention sometimes using a similar laugh.