The only reason I'm not sold on everything is because RJ is still on the roster. If they can move RJ, I have high expectations of the kid. Not that I expect some 19 year old to come in and turn a fringe contender into a legit one; that would be unreasonable.
I have high expectations because of what the Spurs did and how they don't miss when they do things like this. Many things happen along the way sometimes that dictate how a player performs, but the Spurs are banking on him somewhat from a talent perspective.
If you move RJ, and replace him with a true defensive, rebounding 3, I have no doubt that while the overall talent may dip, the team will be more balanced and better off.