I for one dislike the design style of flat sand bottoms with varying degrees of vertical grass faces often associated with Macdonald and his protoges. They are unnatural in appearance and, as Mike suggests, do not work very well under most maintenance practices. Elderly players find it almost impossible to play off the slopes when balls are stopped on the grass faces. It is one thing to retort that they shouldn't be in there, but it is another matter altogether when recovery is impossible or nearly so. Sand flashed higher looks better to some but more importantly is psychologically intimidating and funcitions better.
The vertical faces that were done at Fox Chapel and elsewhere have proved to be difficult to maintain and unpopular with many members.
Perfectly flat sand bottoms are rarely found in nature are plain looking and plain boring. They offer no variety of stances and recovery options, relying merely on depth to present difficulty. Balls that land at the bottom of vertical faces may have the strategic result of steep pot bunkers in the UK but the trade-off is they look terrible (unnaturally geometric) and balls can get caught up in the grass faces.
I overwhelmingly prefer undulating sand floors and higher sand on the faces of bunkers for shot testing demands as well as functional, psychological and aesthetic reasons.
I would enjoy seeing early photos of Fox Chapel, Mountain Lake and other courses to see what was intended and how that relates to the modern presentations. Perhaps the geometric look that functions rather poorly is not of the original design but the result of an evolutionary process with some flaws.
Mike,
I know you played in some particularly hairy bunkers lately. It can be hard to find the ball and difficult to chop out of the fine fescue. When you are in the bunkers, they are functionally deeper because you have to recover above the grass surrounds to avoid being caught by the long and strong grasses. I like this on a true championship course, especially one presented that way on a daily basis. However, it would get tiring to most on a members' club or a club without a second course with a different demand.