Why wouldn't you go to a place that will pay you a lot more than another place? I would.
Now...BYU has a LOT of complications to be hired at t he university as a HC. Namely, you need to be a good standing LDS member. Sooo...how many active LDS D1 coaches are there out there? Are we always in the mode of training up a new coach? If we are...then expect the same mediocre results...unless we get a budding LDS version of an Urban Meyer. But how likely is that?
So...KW is an 'experienced' HC and an active, good standing member at that. If he was hired, I would not freak out at all, and would hope he transforms BYU into a national contender. Why would I wish any ill will towards him? It's a "JOB". He has a good 'job' at Utah. Utah is/was smart to hire an active LDS head coach to handle all the active, good standing LDS families concerned with the environments they send their son to at the college level. It's a great strategy on the U's point of view to battle the advantage that BYU has for LDS recruits. It's not personal, just business.