Green Hills is handicapped quite severely by the up-and-down, claustrophobic nature of the property (too many trees), but I think Mackenzie made a decent fist of what he had to work with. In particular, the bunker work is very nice and sprawling, and there are one or two holes (a long, sweeping, uphill dogleg to the left through a chute of trees followed by a par 3 to a Rube Goldberg, Pasatiempo-ian, multi-tiered green) which I remember quite vividly even 10 years after my one fleeting visit.
I'm told by a friend that when they held US Open regional qualifying at GH, the greens were cut so low and the pins tucked on such severe slopes that some truly ridiculous things were happening: people hitting 30-foot putts which horseshoed around the hole and came back to their feet; people missing six-foot putts by 40 *yards* (balls rolling down into the fairway). Not that these are descriptions of good architecture, but that must have been a fun regional to watch...
Cheers,
Darren