This isn't the NFL draft, first round picks aren't all going to be starters. Go back and look at some older drafts, if you get a late lottery pick that becomes a solid rotation guy, it's a good pick.
You also said he could score 15-20 a game. What 7/8 guy in the NBA scores that much? Nobody. I will be shocked if Jimmer amounts to much in the NBA. This isn't the Mountain West conference. He isn't going to get 30 shots a game. I hope I'm wrong as I like Jimmer