After watching all day yesterday, I thought Erin Hills acquitted itself very well, but I did not see the bunkers as being revolutionary. There were a couple of difficult, cramped bunker shots off downhill lies, and even those, the pros pulled off with ease. There were lots of holes where the short grass around the green seemed to be more of a hazard than the bunkers, last but not least the 18th.
The bunker sand is certainly different than the Tour players are used to seeing, with some gravelly bits in there; between that and the downhill lies, I saw several blast-and-run shots that I haven't seen on Tour for quite a while. That's an adjustment that some players probably struggled with. It was very interesting for play and for spectating, but the poor mechanic at Erin HIlls has got to be sick of it