Scott,
You're welcome.
There might also be a connection to the choice of sites.
Deep bunkers are somewhat dependent upon proper drainage which can be a function of location.
The ODG's may have had more favorable conditions to work with.
I can't remember ever seeing a picture of an olde golfer putt out of one of the ODG's bunkers, yet, I've seen a good number of ODG courses rearrange the sand such that it slopes from the floor to the lip of the bunker, allowing for putting out of the bunker.
However, I've seen a number of bunkers on modern courses that tend to be shallow, allowing for such play.
I believe that in the great majority of cases, when the bunker is below the putting surface, that depth determines difficult for most golfers.
The deeper the bunker, the more penal/strategic it becomes.