Great question Andy!
Some here look at whispy bunker edges and call that minimalism, some look at any lack of containment and call that minimalism, and others consider it moving little earth. Others might say a minimum of artifical hazards, period.
I recall Tom Doak in a 1994 Golf World article saying that he occaisionally would move a lot of earth to create a miniimalistic look (not an exact quote) so the moving earth thing can't quite be it, by most peoples standards.
I think some folks consider an attempt to replicate the Golden Age minimalism, but isn't that more "classicism?". Perhaps a good technical definition of minimalism would be moving as little earth as possible, using every ridge and fold of ground as hazards and building as few articfical hazards as possible. Given the variety of sites, those numbers could vary, and courses could be minimalist if moving 10,000 or 500,000 yards of dirt, depending on site conditions, as long as they didn't move anymore than was necessary.
Really, in the end, I guess if the definition of minimalism is fuzzy, no one really gets hurt, so I'm not going to get a headache over any of it. It will be interesting to see what answers you get.