How would he have less play time at UK? Their whole OAD system is predicated on guys leaving after one year, usually in groups of 4 or 5. If Cal has targeted him as his top SG target then he will most likely get him because he will be playing starter minutes there this year in a role similar to Jamal Murray this past season.
And yes your play is what primarily gets you drafted, but it's become clear that players who play at UK get way more draft talk than guys at other schools. Perception is often the reality, and right now the average joe watching sportscenter in the break room sees a special segment just for the latest UK commit, and to most casual viewers they assume each new commit they get will be a big time pick come draft time without knowing anything about the kid. And can you blame them? It seems like half the lottery is coming from one school each year now, and even their less hyped guys are excelling in the league (Devin Booker is looking like an all star and guys like Archie Goodwin that we all forgot about are showing lots of potential). Scouts and fans of NBA franchises see this and it makes spending a valuable draft pick on you easier, especially if the casual fans can get behind it (see how much trash Knicks organization got for taking a guy like Porzingis, despite him possibly being the best player in that draft when it's all said and done). Anyway, nothing would make me happier to see Diallo at UConn, I'm just saying based on his interviews and factors at play in this decision as an impartial non-fan of either schools, it'll be a tough get. It's purely a business decision at his level of recruitment.