I would say Fultz is in a tier by himself because his floor is so high. After that, the 2nd overall pick would be nice because they'd have their choice of whomever remains. However, I would not be devastated between a difference of 2-4 because I don't think there is a humongous disparity in terms of potential between the top 5: Ball, Fox, Tatum, and Jackson.
I could be convinced with the argument that Ball has the basketball IQ and intangibles that a star needs to have, along with great size for his position. It's just that his dad's politicking and the fact that we already have Thomas (and Smart, and Rozier) kind of give me pause. I suppose in the end they still have to take the BPA though.
There's also the possibility that Ball could play both guard positions at least temporarily, something that D'Aaron Fox cannot do. So there's an argument for still getting the 2nd pick and not having your fate determined by teams ahead of you.