Re: james johnson
I think if he left this year he would go early in the 2nd round. His biggest problem is his shooting. At probably 6-7 he is going to have to play more SF in the NBA. That will mean being able to hit more shots from the outside. With that said, if he comes back next year and has improved his shot, he could add 5ppg to his numbers, and rocket up the draft board. His other issue will be his ball handling, but that is again something that should be fixable.
As you point out, he hasn't gotten any hype. I'm sure some people wonder if he is just the best player on an average team. He is going to have to lead Wake into the tournament before anyone considers him a serious prospect and the best ACC prospect which really isn't saying a whole lot right now.
The other big issue in terms of where he would go in the draft is that in his class alone he has guys like Davon Jefferson, Kyle Singler, Austin Daye, Donte Greene, Anthony Randolph, Kevin Love, Pattrick Patterson, and Blake Griffin who would probably go ahead of him. It would be tough to move past a lot of those guys.
What he needs to do in terms of becoming a better NBA prospect (which may not be the best for him as a college player) is work on his outside shot, become more comfortable with the ball in his hands, and just continue to work hard in the gym in the offseason. Next year with a lot of guys likely out of the way after this draft, he can begin to get some attention and move up the draft boards.
And as far as college basketball goes, Hansbrough could be back and if not Ellington, Singler, Vasquez, McClinton, and Rivers would all be more likely ACC POY candidates. Maybe in 2 years.