Regarding Oubre, I don't think he's that risky. He got off to a slow start at Kansas and so people underrated him a little relative to Johnson, IMO. I think the attitude issue is overblown. As long as the guy has some iq and doesn't try to rob a liquor store, I don't think the risk is that great. These things about not making a consistent effort, having maturity, etc. were some of the same things people said about Paul George as a sophomore.
Oubre is a more talented version of Rodney Hood. He's got a very similar shot, but he's younger, plays better defense, is quicker, and has more of an in-between game. His scoring instincts around the basket are close to elite. If he grows an inch or two and develops physically, we could be looking at a pretty good 2-way player--maybe a Rudy Gay who can actually shoot.
I think the biggest risk/reward wings are Winslow and Johnson, since they aren't consistent shooters and their size/strength advantage won't hold in the pros.