My largest fears with Campbell have always been Ohio State (#1 with some emphasis) and Notre Dame (#2 and way ahead of the field, given Campbell is Catholic and loves the history of that program). I know losing the Orlando bowl game last year was unpleasant, but I almost hope that it might have a silver lining. Campbell got the ISU job by "passing the audition" against us, while he clearly had a rake hit him in the face against the Irish.
After that, you have to worry about your smattering of near-elite but not quite OSU/ND schools from the Midwest, mostly Michigan, Penn State, and maybe Michigan State, but Campbell seems to feel he is above even those.
I think we are blessed the two NFL franchises in Ohio are basket cases -- the Bengals somehow worse than the Browns. Some regional NFL teams are relatively well-run, such as Indianapolis and Pittsburgh, but they seem pretty set on their coaches. Heck, Tomlin has been head coach since 2007 and is only 48 years old.