Mike Bowline:
The degree and severity of bunkering, be they fairway or greenside is an interesting one. The entire concept sort of falls into two basic schools of thought, in my opinion:
1. That bunkering should allow for an heroic recovery shot. This sort of philosophy tends toward the idea that fairway bunkering should be shallower (or that its front face should be more gradual) than green-side bunkering to accomplish this purpose. Interestingly, this philosophy was very much Hugh Wilson's of Merion. He may even have come up with the idea or at least been the one to start it into common use in American golf, thereby creating what Ron Prichard believes to be the prototypical American bunker style and shape. The so-called "White Faces of Merion" were intended not to just promote maximum visibility to the golfer playing towards them but the gradual sand flashed faces of the fairway bunkers were also designed and constructed to promote the heroic recovery shot by allowing the player to potentially hit the ball farther out of them.
2. That bunkers should be of random depths and formations regardless of where they are to create something of a random strategic presentation and experience for the golfer. In this way the golfer must come to know individual bunkers by experience and to deal with them strategically accordingly.
The former philosophy, in my opinion, tends toward formulaics and standardizations in golf and architecture, something I, personally, don't much like although I admit most golfers apparently do. The latter philosophy I believe to be one promoted and endorsed by golfers and architects who tend more towards random (natural) offerings in architecture believing it to be more atuned to the makeup of raw nature and its randomly shaped land forms.