I think this has turned into a "Defending Tiago Because Someone Said He Sucks" thread. I think Tiago is playing great. I think Jefferson is much better than Tiago. I recall seeing Jefferson do well in pick and rolls, he has a good midrange jumper, and he is good in the post. Defensively, he rebounds more and has more blocked shots, which automatically makes him a better defender.
So in summation, Tiago doesn't suck, Jefferson is better, if Utah wants to do the trade for some strange reason, you do it. But I don't think they will, so this is all probably moot.