@SimpleBluff: I actually found a few videos saying this WILL Affect AngryJoe, and I do believe there's a video around the first page that said that AngryJoe discussed this with ReviewTechUSA, but right now, this is just speculation, so I honestly can't say for certain on that subject all together, so you might be right on that. However, Angry Joe DOES use Game Footage in his reviews, so I am somewhat certain this does have some hold on that decision.
And on the topic of LP's, There's a few things I want to say: 1. If someone buys a game, it's their property. If someone uses a straight rip from a game, that's copyright. If someone does commentary and criticism while streaming a playthrough of a game, that's being a Let's Player/Reviewer. However, like many have said before, it's not easy doing a LP Channel, because of all the factors people have said, but however, in order to stay successful, very few people here have said one factor that makes the difference between a good Let's Player and a bad one, as well as how much work one puts into those projects: Quality Control. Anyone with a decent amount of money can begin a LP (Well, not anymore, but you get the idea) but Quality Control will depend on how much you can do. If you do solid Quality Control where everything is entertaining, informative, and with good material and resources at a regular basis, you get more viewers, but that requires constant work (For some who were against this idea, why don't you show us YOUR Youtube Area and see if you have Quality Control down Perfectly. If you don't, you need to bow out on this one), and if you don't, it really shows what's your best and worst works.
2. Yes, I do agree that Let's Players should be paid for their work, which is what Youtube did, and considering they're giving the game companies free advertisement, it's a double-edged sword. Because if it's a good game, people will buy it, and yes, watching a game does make some might not want to buy it, but some people want to try games for themselves after watching, that much is true, considering I bought Metal Gear Rising just because of Two Best Friends Play. However, some people are saying they are stealing from game companies. That is both true and false. It's true because they are streaming their games on the internet for all to see with their own commentary and criticism, and they are getting paid for it, but that is because it is a "derivative work" based on the developer/publisher's game, which puts it on the middle ground. However, that is false because although they are getting paid from Youtube, it's not as much as you would like to think, since people think Ad Revenue must be thousands and thousands of dollars, I can honestly say, it's not. It's at best WAY less than minimum wage for those with only 1k-10k Subscribers, closer to minimum wage with those 10k-100k, and at minimum wage and higher for those at 100k+ (And I know I may be incorrect, but that's my perspective) and at the end of the day, even the best LP's don't make even close to as much money as the Development Studios or the Publishers of Those Games. And even then, they technically aren't losing money, in fact, they're gaining more notoriety, good or bad, and that, as a result, can make both parties even more money, or make the developers/publishers lose money if the game is just outright terrible. It's an honest 50/50 there, especially if it's a bad game (But bad games don't deserve to make money in my opinion, even IF good people made it, it would just perpetuate the cycle of even more bad games. For example: Quantic Dream, enough said.)
3. In the end, this will lead to either three outcomes: A- The Let's Players of Youtube will migrate to another area and perform their works there, hoping to impress the game companies and hopefully find some footing to do their jobs on a more professional level/ B- The major game companies will begin hiring their own Let's Players to comment and criticize their games, only the players will do it on their terms and their demands, meaning a more dishonest and possibly shameful playthrough instead of a more honest and bold one, hell, they may even make game reviewing magazines do the dirty deed for them since they know how to hype up games/ C- In time, and after a lengthy debate on all matters involving copyright laws and such, we will know a true sense of peace where let's players can continue their work, and certain companies will feel the right hand of the law for their fowl play.
Eitherway, those are my thoughts on those matters.