As much as I like Derozan, I beleive he will regress if we trade Bargnani. In the small sample of games without Andrea Demar has struggled. Coincidence? I think not.
Even though Andrea is infamously the worst defensive center in the league, and quite possibly the worst defensive player in general, for the sake of argument, I will agree with you: he is an absolute gem, shooting 0.448 from the field at seven feet. So given Andrea is a gem, how is DeMar a disappointment? His sophmore season has been at least as good as Andrea's; therefore, he is theoretically en route to be at least as good as Andrea: an gem to every other GM in the league.
DeMar is still a sophmore, 21 years of age. Even if he was significantly less productive than he is currently, say as productive as Andrea was in his sophmore season, he still has plenty of time to make an All-Star of himself.
I think we need to wait another year or two to even begin to pass judgment on whether DeMar has lived up to the potential we gave him, regardless of statistics. Relax.