Coaches have way too much power in north american sports, I think that's one of the inefficiencies we will see fixed in the future. Good GM's are becoming very data driven (the effect of Gritensity can be proven through data as well) only to have their coach take a fat shit on the roster composition and play the lineup the way his "gut" thinks it should be played.
I wouldn't be surprised to see it start happening the NBA more in the future first, the European football styled manager who deals with player transfer, contracts, roster deployment and tactics and then that to take the usual 7 years for the NHL to figure it out. The NBA has dabbled with it in the past but it always works backwards, a great coach moves to the front office.