Was never really a fan of RNK... I found it to be a tricked-up layout with a very harsh penalty for missing narrow fairways... lots of fescue, numerous forced-carries off the tee, and then 15 minutes spent looking for balls from tee shots every other hole, etc.
Not to mention extremely overpriced. I recall paying close to $100 to play there during the late fall, and this was nearly a decade ago.
NKR was a perfect example of a layout that was basically designed for the more accomplished players and much too penal for the average players.
If I was designing a course today - my focus wouldn't be on making it overly difficult, but rather overly enjoyable to play. It would probably cost less to maintain it, leading to a more affordable daily fee, leading to a quicker round of golf.
Most golfers don't favor demanding layouts. They wanna have fun, have a few birdie chances. And a lot of times it really doesn't matter which tee box is being played, especially when faced with narrower fairways.
If I shoot a good score at a place and am pleased with the overall conditions (and good greens) - I'm probably going back there to play at some point in the season, even as a private club member who occasionally travels to play other public layouts.
The difficulty rating appeals not to most weekend players of average ability.