Pete,
I don't believe the original question has been answered, is there an inherent flaw to Meridens? You very thoroughly responded to my question of ID on "Dad's old gun" a couple weeks ago. The flawI,m aware of, if you consider it a flaw, is that Meridens shoot loose. I attribute this to heavy loads shot through them for 3/4 of a century and believe some of the more desireable guns suffer from a similar end result. I suspect you're interested in keeping the market dampened on this cool old brand! Yes, the Model 18 is a hardware gun, but weren't many of the others, Sterlingworth/LC/Baker/etc. in about the same price range in their day?
Steve
There are a lot of makers who simply do not have the name recognition. Rocketman takes account of this in his spreadsheet which was developed for English guns, but it can be applied to many markets. There is no flaw in the design.
This by Pete a few posts back would appear to me to be your answer.