The Bulls' biggest problem was revealed in the 2011 Easter Conference Finals: they don't have a second option who can consistently create his own shot. Al could give them that. Plus, with Rose reportedly going to miss most of the 12-13 regular season, maybe the Chicago FO feels they need more scoring for the start of the season. I can sorta see why they would do this.
As far as the Jazz are concerned, I think I would be in favor of this. We would likely miss out on a chance to sign Harden, but a Noah/Favors combo would secure our front court for at least the next four years. Then, if Kanter develops into the player many of us believe he can, Favors/Kanter/Noah just sounds too good to be true.
I doubt this actually happens, but it would have me excited if it did.