I dont think Exum is really that far off of where the Jazz expected him to be. So you are basically saying Burke + no. 5 pick for Teague. Thats a steep price for a fringe all-star.
The Jazz dont NEED Exum to help a ton the next few years (obviously it would be nice). Nobody goes from rebuild/lotto team to championship in 2 years. The goal in that period is playoff experience. When they will really need him is 3-5 years down the road, at which point Teague will be on the wrong side of his prime. You hear Dennis Lindsey talk about not skipping steps all the time, and pushing all in with Exum for Teague would be doing just that. Exums development will determine whether the Jazz reach legitimate contender status and im just not sure Teague gets you there.. I also disagree that Exums offensive upside is limited. He has a LONG way to go, but the tools are there. Players who came into the league without a jumper become solid shooters all the time, and his speed and vision alone give him solid offensive potential