It was also reported he shot well during the pre-draft process. I think the concern may have been the lack of improvement from his freshman to sophomore year. Some of what I've seen on people who scout college ball was they expected him to shoot better his sophomore year because his form was good, but got down on him not only for not shooting well but for not even attempting to shoot as much as they thought he should.
I understand why he fell, the point I was trying to allude to was the Suns seemed to be more dialed in on how the draft was going to play out than they had in years past. Compare it to when they selected Cam Johnson, who everyone was up in arms about being over drafted and they should have traded back to maximize value.