I am making an assumption that Leavitt would keep most of this staff. I am probably wrong, but for now I will assume that. No judgment on whether that is a good or bad thing.
After that, my personal opinion is that Leavitt is as good as 79 year old Bill.
On X's and O's and the details of running a program, I think Leavit would be as good as 79 year old Bill. Leavitt built a program from NOTHING to decent/solid. That is a MASSIVE undertaking that PROVES good management skill. I am confident in this assessment.
On recruiting, I would bet on Leavitt being better. And, not just because you can't get much worse than Bill. Because Leavitt has been more places and participated in different approaches. He has been "on the recruiting" trail more than Bill.
On game day, we have reason to believe that Bill is either significantly less involved than he was in the past, and/or actually a cause of disharmony from time to time these days. At the least, I call this a push with Leavitt.
I will accept and support Leavitt as head coach, if that is what happens.