are these:

1) He will be at minimum an above-average defender.
2) He has already shown the ability to become a decent outside shooter.
3) He has shown that he has the court vision and instincts to become a good passer.

For comparison purposes, I feel like that puts his "floor" at somewhere around Shaun Livingston - an oversized point guard who is a plus defender (although Livingston doesn't shoot threes, like, AT ALL). His ceiling? That's much harder to project. Exum's two biggest deficiencies thus far are that he isn't aggressive enough on offense, and specifically that even when he tries to finish in the paint he struggles. I think that he will improve on that somewhat as he becomes physically stronger, but I don't ever see that being a "strength" for him. He's not going to be Russell Westbrook. Maybe the best "ceiling" I could come up with for him would be if Gary Payton had not been as good of a finisher at the rim? There's not really a good comp currently in the league, I don't think.