Retread coaches often never achieve what they had done in the past, especially those who have achieved success at major schools. Dennis Erickson and Rick Neuheisel being being Exhibits "A" and "B". Lou Holtz and Spurrier at South Carolina did okay, but not great. Mike Price at UTEP. Houston Nutt at Ole Miss. John Robinson's 2nd time around at USC was just slightly better than mediocre. And the list goes on.
Obviously, some have managed to bring success to new schools during their upward climb (Urban Meyer), but it seems they are in the minority.
There's no reason one or both of the Arizona schools can't be much, much better. It's not like they are stuck out on the Palouse like WashState.