Correction - they used him as bait to get Jack Nicholson to sign on as the Joker, then they released Williams after he had already signed on. Then, I think they had the nerve to approach him about the Riddler, but he passed due to that incident.
Oh, and I would have edited my original reply, but the forum is stuck on stupid and seems to think I posed it 7 hours ago, instead of a few minutes ago.
Eh, Williams would have made a terrible Riddler, just like Carrey did. The character is not some zany Joker-clone. He's a highly intelligent man who is obsessed with puzzles to the point of insanity. To that end, Kevin Spacey or James Spader would have been perfect.
Now, onto the topic at hand...
I watched this trailer and felt existentially violated.
Will Smith is the wrong person for the role of Genie simply because the little snippet we saw was him acting like Will Smith in Smurf cosplay.
Also, Jafar is supposed to be menacing. This guy is about as menacing as the head of a high school A/V club. After he said "Bring me the lamp," I half expected him to whip out an inhaler and take a puff.