Completely disagree. You are going to trade three players to move up ONE spot, and that spot isn't a sure thing? Awful trade.
In general I'd agree. But in this case, it's a second round pick (which admittedly the Jazz have been decent in finding decent players), Bell (who I wouldn't care if the Jazz got nothing in return for) and Tomic (who is the worst part of this deal, but I'm not sure if he'll ever play over here anyway), so if the Jazz love Williams enough that trade would make sense to me.