Well count me in then as someone that also knows nothing about great architecture, because I think 5-13 on the River course are stellar. The Valley nine (if you use the original #10 tee) is also very strong and an arguement can be made that it is the better stretch of holes. They don't use the newer River holes for the Women's Open because it wouldn't be easy to move people and infrastructure to that part of the course.
I believe the most playble course in Kohler is the Straits. To me from the right set of tees a score can be registered on that course, where the two BWR tracks are very difficult to score on. To the OP, I was not expecting much from the Irish when I played it, so I was pleasantly surprised with how much I enjoyed it. Matt is right that it is over the top, and I can see that many would not like it, but I kind of did anyway. That being said, I would not miss 5-13 on the River to play the Irish. The front nine on the Meadow suffer in comparison but those holes are not anywhere near as bad as many make them out to be. #1 is a stinker, but in all I believe it is still interesting golf.