To the OP,
Not trying to be disrespectful, I just don't see how this is helpful for an individual setting up his or her bike. Our physical attributes dictate bike set up, regardless of our status as a pro rider or not. Perhaps I am missing the point, but I'll stick to the plum bob when setting up a bikes saddle position. What anyone else does is not my concern.
As to weight distribution, IMO a very important attribute for a well handling machine, that is best dictated by the bike's geometry. (I love custom frames). I would not risk my knees trying to alter my weight distribution by compromising fit
The idea of this thread and this information is to counter the BS assertion that pros run ungodly amounts of setback to compensate for the puny frames they ride; that no Fred or weekend warrior “needs” pro setback. The people searching the internet for fit advice are more likely to be amateur riders without enough experience to know where to start. The more people that can learn to appreciate some setback instead of being basically in the pushup position on their bikes, the better. Nonetheless, I specifically stated that this could be geared toward the racing/go-fast crowd to make for a more apples-to-apples approach. Arguably, pros are the world's most efficient riders on their machines, so just about everybody could benefit from some aspect of their fit.
It may seem like a useless measurement, but with KOPS more likely to be an incidental finding than a desired endpoint (especially since cranks parallel to the ground is NOT the point of max power/force in the pedal stroke), this is a pretty useful way to check your own fit against a pretty professionally fitted crowd. Your statement works both ways. Were I to use a plumb bob and set myself up for KOPS, I'd have 65% of my weight on my hands. Since you also state I shouldn't be compromising weight distribution, perhaps you need to reevaluate the effectiveness of your advice. Apparently, Dan Empfield came to a pretty similar conclusion about avg % setback and felt the need to write an article. Maybe you should swing by slowtwitch and tell him “no offense but...”
I've been thinking about the upper-leg/lower-leg length issue as well. Considering how the % setback-to-saddle height changes markedly with height, I'm wondering if increased height (6'0”+) exaggerates these measurements, resulting in the 11%+ for guys like Boonen, Hincapie, Cancellara, etc. The other side of that are the short riders with the 3-5% setback measurements.
For the majority of people, though, this is a better starting point than KOPS. As I believe KOPS is an incidental finding, a person of average height and average inseam could stat at 9% and move themselves forward or back by a mm or two and probably be in the correct spot behind the bottom bracket ina single ride.