Toe
All-American
Why get rid of most of his staff? Get rid of all of them. The new coach decides who his assistants and support staff are. I guess if the new coach decides he wants to retain some people, that's okay, but based on the performance of this staff, I would personally send them all packing.
If it's true that Parella and D. Williams want the D to play more aggressively and it's Diaco that's holding them back, I'd say there's at least some case to be made for keeping them around.