Klay's not getting dealt here simply due to finances.
People seem to ignore that stuff... When a player is that close to an extension, it kind of kills their value. If you get youth, you want that youth to be relatively early in their contract. Klay Thompson is a bargain now, but what's his value when he's making 3 times what he's making now?
Regardless, as
@Malta said, Golden State is one of the top 3-5 most aggressive teams in the league right now in terms of trading. They have new owner syndrome and are trying to win a championship.
The 4th pick for David Lee would be fukking retarded for the Magic to do. Considering who could drop, I don't even think I'd do the 12th pick for Lee either.