Not so long ago I would have said Williams, no question, but he has shown some cracks in his game recently, especially some inconsistency in his shot.
Walker is a pretty confident player on O, but plays little D, while Williams shows the desire to guard an opponent, even if he makes mental mistakes now and then. On D I respect effort, and expect consistency in decision making to come later.
Given the fact that Walker can play the 2/3, and Williams the 3/4, it seems like they can coexist.
If push comes to shove I lean toward Williams because of his defensive ability.
No man is happy without a delusion of some kind. Delusions are as necessary to our happiness as realities- C.N. Bovee