I can already see some problems using the rarity scale as defined. Published mintages could be very inaccurate from the word go whereas actual mintage could be more accurate but surviving mintage, if it can be determined, would be the most accurate determinant of the rarity scale.
Secondly, the practice of contrived low mintage, which is commonly used nowadays, accords a coin or medal a rarity scale that is artificially low, thereby boosting its purported value. But this value may not stand rigorous market force dynamics leaving the hapless collector/investor clutching a bag of low value metals.
Thanks for the article; another easy read informative thought provoking piece!