Charles Matthews vs Duncan Robinson isn't necessarily the right comparison when you are asking if you'd rather have a shooter/skill guy and build his athleticism or an athlete and teach him to shoot and pass. Matthews shot well in HS and went to KY and Robinson went to DIII. How about, say, guys who are similarly ranked, like Jordan Poole vs Brent Petway?
The real answer is that unless you are getting a top 10 maybe top 25 guy, he's going to have to work on things, and the better talent evaluators can spot the lower ranked guys who are likely to improve on their weaknesses and be able to translate their strengths to the next level.
It is encouraging to hear Matthews is looking good already. I'm pretty excited about the group going forward and he's a big part of that.