JMEvensky,
I tend to agree with your comment but this often comes down to personal preference. I've never been a big fan of the TV commentator stating, "He's better off in that bunker Johnny - it's a much easier shot from there". On the other hand, one could say that "the hazard" is really much more than just the sand, which in the case of Merion's bunkers, is surely the case. The sand there is actually the least hazardous part of the "bunker".
Moreover, I like bunkers that gather balls into them. Rough in front of bunkers (especially fairway bunkers) tends to keep balls out which mitigates the intent of the hazard. I call bunkers that are near the fairway but surrounded by rough, "rough" bunkers vs. calling them "fairway" bunkers. Matt might be experimenting with the different looks/playing characteristics which is why they are finished off the way they are. Adds a little variety.
Mark