Like many other players I think, even other players in this draft like Holland, Buzellis or Carter in his first years at college. This was his first season with starter minutes and onlye try 1 3pt shot per game, it's harder to solve things when you don't try. The year before he was 5/16 from 3, 31%.
Fox with Kentucky had a 24% 3pt season. Davion in his first college season 28%. Even one of our best shooters, Keegan, was 29%
I don't know why he can't improve with the years, sure he'll never be an elite shooter but maybe a 34/35% one which can make him a starter level player with his terrific defense why not? Herb Jones shot at 29, 26, 07!!% before his senior year when he shot 35% and now is a +40% in the max level.