Just watched some more scouting reports on him. I think Williams would flourish very well under the Spurs' development staff. Things like making the right pass, not fouling and footwork are basic fundamental things in this franchise. He also seems to be a smart enough player where you can say that he's able to develop well in those areas. Defensively he seems to be a game changer. His length gives him the possibility to guard roll man and handler in the pick & roll and to contest shots on the perimeter even when players create separation. Not many bigs in the NBA can do that.
I think he'd be the target in the draft. Ideally the Spurs grab BPA at 9 and then try to trade up to draft Williams. Although there's a high chance that the Hornets draft him at 13.