That's an important question, David, and I'd bet there are people here up for a serious discussion. To me, there are two parts to it: what's a good percentage of people missing C2, and what happens to the people who do miss it?
I don't have a percentage in mind, but it seems clear that if everyone hits C2 (and not C1) in regulation, then we're now just looking at a putting competition.
And if most of the people who miss C2 wind up 65' to 200' from the pin, then we have a problem with the dreaded NAGS*. No fun for players, and no fun for spectators.
Sticking with the two holes I used as examples (Harmony Bends #14 and #11), I hadn't seen it yet, so I looked at the finals of the Selinske from this summer.
https://www.youtube.com/watch?v=UFgRcz5lePQ
These guys are using the "regular" pins from the Blue tees, but watching them gives us a good indication what happens on the Gold layout. On #14, which is a par three, there are three gaps, all pretty close to the tee, so people who miss a gap will have some serious scrambling to do, and most people who hit a gap will get to at least C2.
On #11, all four of these guys played it great and had pretty much tap-in birdies. But the Gold pin is 104' longer and is much closer to the creek. The stats I posted previously show that getting to C2 is an achievement, and with all the trouble available, I'm guessing NAGS isn't a big issue. When I have more time, I'll watch MPO coverage from the Mid-America Open and see what we can learn from that.
I'm definitely interested in hearing any ideas anyone has about where we'd want the C2 percentage to be, and how we prevent NAGS problems. Looking forward to the discussion.
*Not A Golf Shot