Im not saying they cant have opinions, everyone can have them. In that sense, the opinions of these content creators are not more important than any other persons, be it a random wow player that never goes on forums or avid forum posters like us. In any case, the people that take part if forums without nothing to gain from it really, deserves more praise than content creators that flush out negative spins on the daily.
That said, what you described is just why these content creators are more happy just making these videos than actually stepping into the industry as a dev. Cause as you said, its alot harder than what content creators do. In any case, you just proved my point. Its much, much easier looking into something from the outside and say "HEY this is shit, fix it! This is how you do it, its easy!" than to actually make a game. Its also a very nice a comfortable spot to be in, cause they generate revenue if wow goes in the shitter or if it flourish. If it goes so bad its shut down(Wont happen in yeaaaars), the very same content creators can just turn around and focus on another game or genre in a heartbeat.
Point is - these content creators make a living from these videos. Never forget it.
Also - im getting the feeling that to many of these content creators have gotten into the habit of being negative towards litterally anything for the sake of it. Whatever it is, theres a negative spin to it.