"But for me it still argues in favor of just learning, finally, to “go native” and learn the original keyboard, which is less of a moving target."
Yes, I mentioned it - same choice was made by many-many people.
I mostly compared not standard with mnemonic but 2 mnemonic approaches - with combinations and 1:1 method. And also think about them based on the volume - and how often one needs to type Russian.
As for Apple - they do have analog MSKLC:
layout editor Ukelele - http://theapplegeek.ru/blog/2010/04/20/redaktirovanie-klaviaturnoj-raskladki-ukelele/
But I mentioned Apple only to underscore that they included into OS such mnemonic layout which was used for years under Mac and Windows - 1:1 one.
So for me it's strange that Microsoft decided to "forget" all those years of 1:1 mnemonic layouts (and it was based on their own MSKLC!) and include into Windows 8 brand new type of mnemonic layout
:-(