I get what you are saying, but it's only fair to let the new coach select his assistants as he sees fit. I didn't like it when TO forced Watson and Gilmore on Bo, and I wouldn't expect the new coach (if one is hired) to be told who to keep around.
If Riley is fired, his assistant coaches will choose to go elsewhere, rather than stick around NU. The only exception would be Parrella, given his previous association with the University and team.