Doesn’t Johnson win in a cakewalk? Of course, the situation that lead to his hiring set him up for disaster from day one, but they went from a middling team to putrid and have stayed there.
You could also clearly argue Bzdelik. Walks into a situation with a decent team and immediately they drop to the bottom and have stayed there, even with some improvement this year.
Gregory has kept GT about where they were, so neither good nor bad. Donahue I don’t feel can be argued as a bad hire. At the time he was hired it looked like an amazing hire, but the potential has never materialized. Brownell has Clemson playing well and in the best position they’ve been in in a while. If he fixes their schedule to go from horrible to okay they might even get themselves over the bubble in future years.
These are all just observations from watching brief snippets of these teams play this year and looking at records. I haven’t done the work to produce hard evidence for my feelings.