Players, specifically with Rick Pitino, but yes in general in college basketball, tend to take a big leap in year 2. Especially guards with Rick. Sim is bigger than Siva and Russ Smith, he can shoot it from all three levels, he's quick as hell and started picking up things late in the year on how to orchestrate from Jenkins.
Things weren't a straight line for him because of how good DJ was and how vital he was to literally everything on the floor, thus stunting what we could see from Sim. But you saw flashes. And so now the plan is to see longer flashes in year 2 while giving him more responsibilities.