Nice analysis. There's no perfect metric, but you certainly tagged some decent ones - lots of miles logged, lots of long flights, high average flight distance. Yes, there are remote soaring sites where you can have a nice time flying not as far or as reliably, or with as many other pilots around, but mostly reliable weather to fly long distances with other soaring pilots seem like decent criteria to first approximation. As a comparison, you might consider taking out OLC flights flown during contests or OLC camps, just to see what the normal organic XC flying looks like when there aren't events being hosted. You could also sort purely by average OLC distance to pick out the hidden gems - but I'm nit-picking.

9B