TLoU 2 review bombing has nothing to do with console wars at all. And considering how low it's user score currently is, it just proves that it has nothing to do with the console wars. The current state of the console market guarantees Sony the majority that will be able to push the score in a positive range in console war scenario.
As for Metacritic itself, it has been known for quite a long time that it's user score can't be taken seriously with a lot of troll scores like "0", "1" and "10". That system is broken so I'm not sure why would anyone even want to use Metacritic "user score" to decide whether the game is good or bad. On a side note, the same can actually be said about "Critic" score. It's all subjective because critics are also just normal people that have their tastes. Which quite often causes some games to be underappreciated by them and some games being overrated for whatever reason.
100 posts is a very harsh limitation. I would propose the better system but unfortunately it will probably only work with Steam/Xbox/PS games. Just require Steam/XBL/PSN integration and check that a certain achievement was gained by the user on account. Almost all games have "completion" achievements which can be used as a requirement to post a review for such game.
Yeah that would work a lot better!