Kalani, Ty, and Tuiaki could be at BYU for a very long time. Coaching consistency outweighs risk of stagnation imo. With no P5 on the horizon, it is important for BYU to have every little recruiting advantage they can get. LDS recruits want to know the coach that recruited them will still be there (along with their scholarship) in two years.
I would like to see Koy join the staff. That would help Ty imo.