David,
There's a difference between a great test for the best players and being one of the best courses in the world. Yes it's a great piece of property and a course of note, but what specifically leads you to believe it's one of the best courses on the planet?
I think the variety of the holes there is excellent and the challenges it poses to good players are fantastic. I've never seen a course of that length that wasn't just bomb it, find it, whack it at the green. I think Bethpage is a perfect example of a course like that. I think it's grossly overrated. It's long for the sake of being long, it has incredibly boring, flat greens and is a paradigm of what is wrong with stretching golf courses to that length. Whereas Erin Hills is long (but plays shorter because of how firm the ground usually is), but rewards shotmaking.
When I played the course, I was fortunate both to: (i) be swinging as well as I would the entirety of that summer and (ii) have a great caddy. There's so much strategy involved in picking lines off the tee to set up an angle for a second shot based on where the pin is and then how to play the approach shot to get it close.
I'll give you an example:
#10: When I played the pin was back right and my caddy told me the best way to get it close was to try and hit the slope 10 yds right of the green and let it feed down, but that the shot there worked best if you were on the right side of the fairway so you could draw it onto the slope helping it kick down.
I'm going to agree with Mike Davis on this one. I think it's a fantastic course and I've played a number of courses on the current US Open "rota." I think EH is much more interesting than, for example, Congressional or Baltusrol.