Assistants were already let go due to underperfoming in recruiting. You usually don't get two bites at the same apple if things aren't going well. An AD might let you change staff, pay buyouts, and pay up for for replacements to fix a problem, but it had better be fixed, or the rest of the program had better be going really well for him to do it all over again.
And that is a good point about Kellie maybe not sticking around if the AD tells her to can her husband. That could be a gambit to get out of her buyout should the AD decide to go that route. I doubt it would work though because Kellie doesn't have any prospects of making anything like the money she is making here so it would be foolish not to ride it out for as long as she can.
Best case is she gets the team playing better and makes a good long run in the tournament. She has plenty of talent to work with, and if she doesn't do it this year there is little prospect of her having enough talent in the future to ever do it here.
I will say this about Mr. Harper though. No one here has any idea if he is a net plus or minus to the program. It is all just speculation. I haven't seen anyone who I think has solid contacts inside the program say anything one way or the other. Maybe others have better contacts and can enlighten us. I think a lot of the opposition to him is knowing he can't be replaced as easily as the others should that be necessary.