I don't think a college program can successfully work this way. The AD is the ultimate decision maker. The head coach runs his or her specific program. You need a head coach who you feel confident in to set the vision and strategy for the program. We feel that way about Fran (for now, anyway). We felt that way about JB for several decades.
The "GM" is a misleading title because people think of it like the pros. It seems to me that college GMs are really a "Director of Player Evaluations, Player Compensation and Analytics". The final decision on player acquisitions and compensation allocation needs to be up to the head coach, IMHO.