>favourite "gaming media influencers" like mindless sheep
Actually no difference, you're just taking the other side of the argument which happens to coincide with one of these "influencers" and their views.
People aren't going to watch someone if they're playing something that the people don't want to watch. For instance, if a popular CSGO streamer is playing Warcraft 3, he's going to get far less viewers - people want the game first, person second. Sure, you will get people that will watch someone play literally anything, but Twitch is about browsing by game, not by person.
Nintendo have already issued a statement saying that certain games cannot be streamed on nicovideo, and then there was that whole thing of them not wanting Smash at EVO so it's not surprising. If someone wanted to stream, say, CSGO, and was unable to do so, they would just simply stream... nothing, come up empty and not stream, which hurts Twitch. I don't assume everyone will actually take this route and want their games off of Twitch entirely (Atlus have never done this for anything other than Persona, not even the mainline Shin Megami Tensei series), but some publishers and developers will.
I'm really surprised this kind of thing hasn't happened earlier, before Twitch, with the likes of Ustream. Companies are entitled to protect their IPs and how they're distributed, people want their works to be bought rather than watched (which is what I just did with a game, in fact) because they're missing out on sales, while the likes of Twitch and Nicovideo are making a profit off of it. Essentially it's no different from streaming movies you've bought and the streaming service being paid for it, or if you're a partner, the streaming service and partly yourself.
Persona is an easily spoiled series (harry potter is the killer-esque), so I'm actually kind of glad this is happening. I don't want to be spoiled on the game.