While my post was more based on providing a counterpoint to the "LPs are free advertising" argument, I think that your points seem to be indicate a scope beyond LPs and more into fair use in general. I'd still be happy to share my opinions though (not that my opinions should count for much).
Well the whole content ID claiming situation affects everybody. There is no discrimination.
Since you were thinking of different scopes this is how I would break down various groups.
1)Let's players - strictly gameplay (story lines are minimal or non existent)
2) Let's Players - Story is prominant
3) Reviewers
4) Parody Performances/Critiques
5) Tournaments
6) Discussion Panels
Every youtube video is scanned for the following parameters
A) Audio Content
B) Video Content
So one problem that comes up is what are publishers selling to us? Art assets, music? Isn't it strictly games?
I would say no they don't strictly sell games. People do buy art assets in the form of collectors items and music as separate tracks.
But what makes a game a product you want to buy is how you interact with it. YOutubers aren't infringing on this interaction. They aren't reverse engineering software. The games aren't being properly experienced as intended through watching them on a video.
So while art and music can be protected the case for videogames is a lot weaker because people typically aren't buying them just for those 2 things.
This is no different from the court case I linked to earlier in this thread about Google scanning and uploading entire books.
Google was protected by fair use even though they are making money off of those scans because they only allow people to read a portion of the uploaded material. They aren't getting the full experience that is intended by publishers and authors.
With that clarified
1) Are protected under Fair Use. The most obvious example of how their works can be transformative performances are speed runners. Speed runners look for flaws in the games systems to drastically reduce play time beyond what is intended.
2) Shouldn't be protected. The most obvious example are Adventure games. These point and click affairs are extremely light on interaction. They are still games but you buy these games so much more for their story more than anything else.
3) Are protected. You already agree with this.
4. Are protected. This is no different from reviews. They are providing an analysis but the scope of that commentary is framed by the game in question.
5) I'm not 100% sure on this one but I believe every major sports organization paids a licensing fee to the inventors of the sport and continue to pay a fee to their families' foundations. Considering that all tournaments are paid for by the players until they grow so big to attract an audience it makes sense for the tournaments to not be protected under fair use because they are having their initial consumer base are the players themselves. This one really needs to be examined heavily though.
6) Are protected for the same reasons as 3 and 4.
Yet all of these videos are being claimed.
So I guess that overall, my stance is that if something would fall under fair use then of course the original copyright holder does not deserve compensation. However, if it doesn't fall under fair use then some sort of licensing agreement should be met. The only reason why all this is a contentious issue is because there is no legal precedent for Let's Plays yet. I think that answers your questions?
That answers it. I disagree that legal precedence doesn't exist even for Let's Players but this mess is so big it's obvious that more than Let's Players are being affected.