6'8" and a half at 17, he should still end up around 6'10" by the time he's drafted, and he actually outplayed Jahlil in their matchup.
Amare was the same height when he came into the league.
Randle is a tweener because he can handle and shoot a little? 6'9" 250 is not a tweener just because dudes like Timmay have made a career out of claiming they are 6'11" forwards. 6'9" 250 and ability to play the post and rebound is exactly what a four is.