Random thoughts:
I find it hard to give the ODG much credit for the greens contours, when (in the case of Ross, for example, he may have only personally visited 25% of his designs, and rarely more than once each.) I saw his field notes for Franklin Hills near Detroit. No notes on contours. Basically stuff like "move green down hill for vision" etc. In fact, very similar to more modern field notes, IHO)
I was also confused by the "single plane" comment. However, I have noticed Doak, CC, etc. have gone away from the Mac "puzzle piece" bunker shaping to long ovals, but never round like RBHarris or Maxwell. More....well....."turd shaped." But, that doesn't have much of a ring to it.......and to create interest, the jagged edge.
BTW, in a conversation, it was pointed out to me that RTJ (mostly through Roger Rulewhich) had a lot of jagged edge bunkers from the late 70's on. Or, at least, ultra squiggley.
Langford wrote an article about what sand bunkers in the Chicago District should look like to mimic nature there, but I haven't found it in my collection yet. If anyone else has it, it might be pertinent, because yes, bunkers are abstract creations, but in naturalist theory, maybe they ought to take their cues from the land around them, which many not contain any sand blowouts. Or not, maybe you use the Japanese Garden theory, where the viewer is presumed to be able to discern the natural influence on obviously man made elements, and go back to Mac's puzzle pieces to represent blowouts in a much more man made way.