Matt,
You might already know this, but most guest play at Whisper Rock is on the Upper, whereas most member play is on the Lower. I do think its very possible for one course to be better for most people for the one round experience, whereas another is better for repeat play. Unfortunately I think the ratings by nature tend toward those "one round" places since that's most often what panelists get to do.
Arizona has courses that are higher, but it still has a lot of courses in that 5-6 range. FH Canyon is probably an 8 for me, and I probably like it better than most. If an average course is supposed to be a 3, I'm not so sure what's wrong with having a bunch of 6's. Most of the courses on the Modern 101-200 list are in that range, right?
The main point of the previous post is that preferences work both ways--some people may dislike desert golf, but others like it more. I think it balances out.