I don't think he has a problem on D. We raved about his D last year in the BET and NCAA. He has the ability to play excellent D. I think he needs a lot more strength, and he needs to learn how to take a hit, and still score. He's a little soft. Both of those are things he can adress better at the next level, with more time on the weights and around stronger players. He needs to go. I think 75% of his problems this year can be attributed to lack of focus and poor team play. He was mentally checked out, and didn't play nearly as hard as last year.
Robinson looked clearly superior to Sullinger head to head. Bigger, longer, stronger, better leaping, faster. Sullinger a slight edge on savvy and moves. Rivers could be good...hard to say. Barnes looks like a project to me. Honestly, even Davis looks like a project. His offense is not really much better than Drummond's and his body isn't close to Drummond's. As a prospect, I'd take AD over Davis ever single time. Higher upside. Davis could/should become Marcus Camby like.
The challenge in the NBA is that a true superstar (Lebron, Wade, Paul, Kobe, Howard) means so much. So while I can project that Sullinger will have a long career, and be a decent player that contibutes, I don't see any chance at stardom. So you need to decide, do I take a chance on a guy who could be a star...knowing that his downside is lower as well, because he's young and untested.