You should temper your expectations of rookie WCS. First, he's a rookie. Second, Wisconsin showed, that Willie lacks awareness and footwork to go through screens/bumps to pursue SFs effectively right now.
Kings are not getting well adjusted 4-year veteran - WCS will have to learn a lot of things, and even though he will have much easier time adjusting to the speed of pro game than SGs from previous drafts, there will be bumps on the road, and if Kings rely on him as 20-25 minutes contributor right from the start, team performance will suffer for a couple of months at least.