He's 6'8" as a HS junior. No hair on his legs or face. Probably still growing. He has the skills of a wing. Nice touch on his shot. Agility for a guy that size is ++. Some guys that size are still a little awkward/clumsy at that age (or older -- think Toney McCray.) Isaiah is fluid. He's fluid, he's smooth, he has a nice build even at his height and weight. He'll be able to add to that frame. Plus, he has the ability to put it on the floor and drive or shoot from the perimeter. He has a lot of tools and a lot of upside. And he seems to have the kind of demeanor that won't be a liability come draft day (see Petteway, Terran.)
Roby will be a great replacement for Shields. possibly an upgrade if he keeps improving.