I think ADs need to stay out of the hiring assistant coaches business. They hire the HC, then let the HC staff the team. And if the HC wants to make changes, you talk budget and salary options nad restraints, then let them do it. Or not. Whatever they decide.
If the AD is involved in making assistant coach hires, then they need to take the heat when it goes wrong.
And seriously, of course the O will be better next year. it is so horrifically bad, how could it not improve? But just improving should not be enough either.