His stock fell dramatically over the course of last season because he played pretty poorly. I think it got to the point where people were questioning if he was even a real prospect or just a big prep school stiff that people had heard of. He recouped some of his value this summer though with good performances at the big events he was involved in.
I saw him play in January at the Hoops Hall Classic and wasn't overly impressed. He played extremely hard, was obviously skilled, and VERY coordinated for a 7 footer but didn't show much skill. I think since then his basketball ability has flashed a bit more.
I find it hard to determine how much of him is a slam dunk prospect versus his handlers trying g to make him LOOK like a slam dunk prospect.
He's not a super young prospect, and he he has enough question marks around him to make me confidently say that he'll never climb above #5 on my 2017 prospect list (Giles, J. Johnson, Tatum, and D. Smith are ballers). That said, if he plays well this season you'll see him move way up again.