Clint, I can tell you that the site that added video has not changed a product description or added any other content other than new products in years and it's rankings were maintained. So argument about expectations of change by Google are, IME, not born out. What they did take advantage of was the shift to universal search and being "ready"
before video was added to SERPs.
That is what SEOs do. You have us mixed up with the scrappers and other Aholes who use
similar techniques and call it SEO because to say we F$%^ with SE isn't very sellable! Nor does it seem like a long term marketing strategy.