I think the sign that he is going to be an all-time great player is his ability to do the amazing instinctively. That move he made against Phoenix, double clutching from his right to left hand is very similar to a move Jordan made in the playoffs some years back. When KK asked him if he had practiced it, he said, I'm paraphrasing, that I didn't realize I did it; it just happened.
Oh, just to reiterate, I was the first here to predict all-time greatness -- I know I will get grief for saying this again as I already did, but I predicted it in October after the Lakers game and saw that amazing dunk in person as I was in the lower bowl near the basket he made the dunk. Maybe others were thinking the same thing, but I was the first to put it in black and white. It's just like Darwin's theory. Others had come up with the theory of evolution but he was the first to publish it so he got the credit. Now let's not get into a debate about evolution, there is more proof for it than there is that Jesus Christ existed.