I've been lucky to be on green committees, and it's interesting and fun. All my experience has involved master plans developed by architects you know and like.
I haven't seen a "too many cooks" scenario at all. Rather, I've seen the close involvement of the superintendent, respect for the architect, and strong support for the master plan. Committee review and input? Maybe one meeting. Not a painful step.
The important reason, IMO, to have a committee of 6 or 8 (let's say) is political. In a good way. That is, informed committee members serve as emissaries to the membership at large, providing information and reasoning. Everything that is this expensive naturally gets membership scrutiny, and committee members can help prevent dumpster fires when the costs are revealed, trees are removed, bunkers changed, etc by communicating with members they know. Committee members provide needed transparency, to use a term much in vogue.
Maybe some clubs can get away with a couple of powerful members jamming a master plan on their membership, but I'm thinking that wouldn't work out very well in the vast majority of cases.