I think Prohm took Hoiberg's identity of run & gun / 3pt mindset as to not completely change the dynamic of those players that played in Fred's system. I think Prohm is starting to construct his own identity as a coach where he wants his teams to be more focused on defense. I also think Prohm wants to be very long and play passing lanes, then push the ball and get to the rim. The reason I say that is the players Prohm has got in next year's class, as well as some of the guys he recruited in the past (Halliburton, THT, Griffin, Leech), fit that mold of a long athletic guy.
Key word being 'think'. It's year 5 and I'm not sure anyone really 'knows'.
Side note iirc his first two teams actually weren't all that run and gun types, and seemed to be more of a half court type compared to prior which really seemed to diminish a guy like McKay aside from his other stuff.
For the record, I'm not in the 'get rid of Prohm crowd' nor am I in the 'Fred would be just killing it' crowd. But if there's many episodes of the team looking completely unprepared from a schematic point, it can't be 'well, the players just don't buy in and he's a young coach who just needs time' as a rationale if they don't know what they're even buying into.