I'm not on the Murray sucks bandwagon and 'regression' is obviously silly, but I do think he's peaked and that peak is.. average.
He plays a different style, but he's a Kirk Cousins level QB. Colt McCoy came and had 2 games that were statistically as good as pretty much all of the games Murray played.
Colt McCoy:
79.6% 35/44 2 TD 0 Int
84.6% 22/26 1 TD 0 Int
I'm not saying McCoy is as good as Murray, but that offense was competent without him. I don't think he's a perennial top 10 QB before I get to the leadership and motivation questions. When you do, it would scare the hell out of me that this is a actually Mahomes brother or spouse.. not a future Mahomes level QB.