I don't think size is Sullinger's problem. He's tall enough at 6'9" to play PF, he has fairly long arms and enough elevation on his jump to play the PF position both offensively and defensively. Sully's problem, in my mind, was his quickness, or lack there of, which I thought would make him too slow to play good defense against other PF's in the league and not having quite enough length to make his power post game translate to the NBA against Centers.
What were my expectations? Role player PF off the bench playing 15 minutes a game behind a good PF on a good team, or marginal starter on a poor team. I am more optimistic in my view of Sullinger's upside, but he's going to have to continue to improve his defense and his craftiness around the hoop to go above those expectations.
OTOH, if he can continue to improve on defense and start to make 15 foot jump shots with consistency, and especially if he can stretch his jump shot out to the 3 pt line he is going to vastly exceed my expectations for him.
He's doing better than I thought he would on both defensive rotations and getting his shot into the basket instead of getting it blocked. I've always liked his "intangibles", but BBIQ and grit aren't enough to be in the core of a championship team. To make the core Sully is going to have to bring one, preferably two, skills to the party: +rebounding, +post game, +defense, +mid-range shot, and/or +3 pt shot.
If I were Danny I wouldn't trade him now. Give him this season to develop. By next year I think DA & Doc will have a very good handle on Sully's top level. If it is "core worthy" then keep him...like DA did with Perk and Rondo. If it is "role player" then he's trade fodder for someone better.
I will say, though, that no matter what Sullinger will need a different type of front court mate than Bass. Those two don't go together at all! Both of them need to be playing with somebody like KG to be most effective. Okay, we are *very* unlikely to get a young KG, but the type needed is a very long, lean, athletic, rim protector. I think someone like Blatche or Mcgee would be a good choice. Fab Melo would be ideal, but he's a project and may never pan out...although signs look pretty good.