I don't think anyone views Sexton as a natural point guard. I think he's viewed as a sparkplug scoring guard off the bench. Whether he has much trade value is a fair question.
The draft is likely perceived to flatten out after the top 4 or 5 picks. Players like Black, Ausar, Hendricks, Walker have been pretty interchangeable in mocks. Maybe that will change, but the early buzz has been that teams like Orlando, Detroit and Indiana are open to moving off their picks. Getting into the Top 4 is probably a different story.