Perk will be fine, Presti knew what he was getting. Much of what Perk does doesn't really show up in the numbers (setting good screens, scaring the bejesus out of people, etc). Doc said as much, and I agree with him. I would not be surprised if Perk's numbers got a little better as he becomes more comfortable with the OKC system, and gets further away from his injury. Trade was still a good idea, though.
Meanwhile, Perk is hitting 40/52 FTs this year, for 76.9%. That's actually pretty good, he's way above league average for Centers, amongst the top ten for people who play a decent amount of MPG.
Take that, Rondo.