I've come to moderate my views about the green on Spyglass #4, but I still believe this: if you're going to build a green like that, don't put the hole where a ball can't come to rest. I know, that seems like common sense, but when I played #4, the pin was all the way up front, and putts from below the hole wanted to roll right back to you if they didn't go in.
The problem, I would assume, is that the greenskeeper needs to move the hole locations around to avoid too much traffic on any one part of the green, but the more fall-away a green is, the fewer available hole locations. Looking at the Blackwolf Run River Course picture above, I'd like to see how much more green there is on the left side of the green (the right side of the picture). From what is visible, it appears that the available hole locations on the right side are very limited. No problem -- as long as the greenskeeper doesn't cross the line.