In my view, bunkers are the most overrated and misused hazards in the game of golf. I watched The Cadillac Championship yesterday on television. The bunkering at Doral's Blue Monster is so over the top and ugly, that it hurts the eyes. Too often bunker are used to make mediocre designs look interesting or dramatic.
If bunkers are used, they should be real traps, like the original ones on links courses. Skill is necessary to avoid and escape them. The opportunity to putt out of a shallow bunker doesn't make any sense. If you want to give players this opportunity, build grass bunkers, Valley of Sin like depressions or run-off areas. More difficult for the better player, easier for the weaker player, better looking and cheaper to maintain.
I strongly disagree. Golf is full of variety, and there is room for shallow bunkers just as much as for deep, penal ones. As the late George Thomas pointed out, the advantage of a shallow bunker is that it makes the next shot more difficult for the player who has missed wide of the green than for the player who has just barely missed it and might be able to putt out.
Also, at a place like Tara Iti which was all sand to start with, there has to be some point where the irrigation and grassing stops and the sand starts. Ironically, the more efficient we are in using turf, the louder some people complain about "too many bunkers" even though it is all just "through the green."
P.S. The historian at Pasatiempo, Bob Beck, pointed out to me that in most of their old photos, it looks like the bunkers were much shallower in Dr. MacKenzie's day, as if you could have putted out of many of them. It's hard to know if this was intended as a feature, or simply a temporary case after the sand was installed. I do believe it was a feature of Riviera and L.A.C.C., too. But the bunkers grew deeper over time, through natural processes [wind erosion and buildup from play] and deliberate intervention [by green chairmen who think like Martin L. does], and over time this aspect of the courses has been lost. We thought about restoring the bunkers at Pasatiempo much shallower, but naturally, the committee didn't want to go that direction because it might make the course "easier."