From Wired (from Vanity Fair):

[T]he most interesting thing VF got from the director is his choice for his favorite Star Wars character: Jar Jar Binks. In bringing up the most widely disliked character in the galaxy far, far away, Lucas was likely defending his past creations. But the choice also touches on why Lucas seems to have stepped away from helming Star Wars movies: freedom from one’s creations. “You go to make a movie and all you do is get criticized and people try to make decisions about what you’re going to do before you do it,” Lucas says. “It’s not much fun, and you can’t experiment … I don’t like that.”

Meesa no souprised. George Lucas didn't mind taking chances with Star Wars, either in tinkering with the originals or making a clownish CGI character a central figure in the first of the prequels. The same spirit that drives the Advanced to be so amazing when they are young drives them to be so confounding when they mature. It's a package deal: you have to take your Wookies with your Gungans.