Mathis will probably finish around 35% from 3 for this year (currently shooting 40% from 3 so far this year) and is averaging 12.5PPG and 4 RPG....if Miller is anywhere close to Mathis as a 3 point shooter (33 -35%), he will be a 75-80% FT shooter (much better form and touch as a HS player).
Mathis out of HS, had a completely different shot form and shooting form and had to rebuild his entire shooting motion and form since HS, but that takes tons of work.....Miller has a much better shooting form based on the game film and game on Sunday.
If Miller is at 70 to 80% from the FT line, he should be a double figures scoring guy with 25 or more minutes a game. If Mathis was a better FT shooter while shooting 40% from 3 this year, he'd be over 15PPG vs 12.5.....
Miller also is more of a combo who can spot up and shoot if you have another guard that can handle or command a team's better defenders. Miller isn't an elite player in any one area, but there are very few holes or drastic deficiency to any parts of his overall game. He's a B in almost every category you would want to grade in a HS prospect.