Fultz and I wouldn't lose any sleep over it.
Ball looks like a fine player, but Fultz looks franchise to me. If you were going to design a PG prospect for the current age, Fultz would basically be it. He has shored up some of his weaknesses (inability to go left) and continues to provide highlight reel plays on the defensive end.
The kid can finish with either hand near the bucket, has the most advanced pull up game I have seen since Kyrie, and has an incredible frame for his position. And if you watch closely, its almost like the game is already slowing down for him. He almost always makes the right offensive play. He has kyrie esque one handed finishes at the rim in some games.
In terms of playmaking, he looks utterly elite. In my opinion, he is second only to Ball, but his offensive game is so far advanced (in terms of scoring) that it isn't a discussion. Fultz' feel for the game harkens a bit to young CP3.
And on top of all that, he has thunder dunks in traffic every couple of games to remind you of how athletic he is. Don't even get me started on the fact that he has multiple pin blocks on the backboard as a pg this year.
The other thing people overlook is that he has incredible versatility. He is almost as deadly playing off the ball as he is at playing on the ball. He can play next to a 2 or a 1, which makes his fit here perfect.
I believe he is a can't miss prospect. I see him as a weird mix between a Kyrie/Harden/D Russell mold.