To be honest, I do like gameplay videos. Personally, I think through common sense that these companies shouldn't have anything to worry about, unless people are showing off videos just for the sake of the story (those exist). For some people who just want to buy a game for its story, they don't have to. I can see a company having a big problem with that.
But for everything else. I can see a personal problem with it. Should Nintendo be forcing youtube LPers to be sharing them ad revenue for games that are more than 10 years old?
There's a lot of grey area on the subject, and I believe there are a lot of uncertainties at this point. Something that real numbers can answer. But nobody has done any real research on the subject.
All I'm saying is that LPers need to be humble and realize when a company like Nintendo does this. It's completely in their rights to do so. No matter how much LPers think they are promoting the company.