Interesting question Ed. First off, I don't have a problem with the depth of the YHC's bunkers; same for Woodhall. I think both clubs get it just about right. My issue with the YHC's greenside bunkering is the repetitive nature of their placement and firmness of the sand. I don't play badly from them, but most of the guys I was with struggled mightily. It was very common for a greenside bunker to be at least a 2 shot penalty. I am not against a 2 shot, 5 shot or pickup penalty from sand, but it shouldn't be a common scene. Of course, most would say the bunkers are too deep and maybe they are right, but I think its a sand issue.
Woodhall has a bit more variety of bunker placement around the greens including many that are set well off the greens and some greens with no bunkering. There is also the added bonus that they are very handsome, perhaps the most attractive bunkers I have experienced. However, personally, I would rather see less greenside bunkering and more happening with the greens to offset that loss of challenge. In the end, just in terms of getting out (not worrying how close one gets to the hole), I think Woodhall's greenside bunkers are more difficult than YHC's at least partly because of how vertical the walls are and one doesn't often get uphill lies. If we take into account sloping greens then YHC's bunkers are probably just as difficult if not moreso. I know I can get out of the sand fairly well, but I rarely had an opportunity to play at holes because the slope of the greens. One has to be an excellent bunker player at YHC to be aggressive. However, I bet most golfers wouldn't draw any distinction of difficulty.
If we are talking about fairway bunkering, YHC is streets ahead of Woodhall. Woodhall's are more difficult by quite a margin, but the placement at YHC is very good.
Ciao