You're picking out two of how many PG's he's faced?
The average NBA PG is taller and more athletic than a college PG, and in the NBA they will switch a SG or even a forward like Kawhai on you. Going against Avery Bradley or Patrick Beverly is far different than going against Kobi Simmons. Hell, their other PG Parker Jackson Cartwright was like 5'9.
A lot of scouts have already said he's going to have to change his shot to be able to shoot in the NBA.
People are too quick to say a college player is going to be a star at the next level. How many point guards has that translated to in the past five years? Elrid Payton? D'Angelo? Dunn? Exum? Mudiay?
He had problems guarding Fox, try Harden or Russ.