Interesting article! The metric you use does eliminate triviality, but it sometimes uses very obscure (and arguably uninteresting words), such as calumnies, ivoriness, coprophagist, etc. That's what you describe as Webster's Second jargon that nobody knows".

It would be interesting if you could adapt your metric to account for general prevalence of the word in English. Scan a giant subsection of say Wikipedia, and assign a frequency to each of the 234,000 words in a map, giving unseen words an infinitely small frequency, and then use the sum or multiple of the frequencies of each of the anagrams to bring out some truly interesting ones!