I feel like people are insisting there is a scenario where publishers are directly paying for coverage. The evidence of this appears to be that there are full-page ads for games, so clearly publishers are controlling the content.
So let me present my bona fides here: I used to be a games writer and I know plenty of people who still are. I have worked at several newspapers, all with sales departments. I have a bachelor's degree in journalism and have edited a book on journalistic ethics. The book was, in part, written by my father.
The scenario you have in your head? It happened once and it was so embarrassing for everyone in the industry that people have made fun of the organization (Gamespot) for years because of it. It happened because Gamespot was losing money and couldn't afford to lose advertisers so they let Sony and Eidos (who was kind of a slimy publisher pre-Square Enix) dictate content control. The people who got fired or left, the people saying right now that the Gamergate concern over ethics is farcical, chose to stand up for their words and opinions. Ethics has always been paramount to 99.9% of game journalists. The people who think that, because there is a Borderlands 2.5 background on a website that the reviewer is encouraged to give it more coverage or a better review, sales (i.e. the department looking to exchange ad space and money) and the editorial staff are separate and there has been a brick wall between them especially since the Gamespot incident. The two groups have no control over each other - they won't turn down an ad because the game is bad, they won't bloat a score because the game is advertising on the site.
The games that are getting huge coverage aren't getting it because the publisher is paying money for coverage. For one, that one be exorbitantly expensive. For two, you don't need to pay someone for coverage. You offer it to them and they'll usually do it because they want to keep people informed and because more content is always better than less. It's not that the AAA games get more coverage because they're spending more, they're spending more so consumers will be interested, and that drives clicks. Lots of people then go read those previews for hyped AAA games BECAUSE YOU, AS A CONSUMER, ARE HYPING THEM. If you didn't want them to cover Destiny, maybe you shouldn't have made it the best-selling new IP in a decade and sold out three waves of pre-orders for a game apparently no one likes (especially, as it turns out, reviewers).
If you want to know why writers don't say "Man, this game sucks," in preview events, it's because they have hope it won't suck and, here's the funny part, because people complain when you do that. Not publishers, you, the reader. They bitch that the writer isn't giving the game a fair chance. Oh no, people don't like Microsoft exclusive Too Human, what a biased site! Oh no, people have concerns about [niche Japanese title], they just hate everything that isn't a western FPS! Then when a game that doesn't entirely deliver gets a non-committal preview, people feel betrayed that the game was not condemned in an alpha state. Game journalists should have smothered it in the crib, they say.
Also, let's talk about embargoes, because this is always the big one. And if you think I'm going to blame you, the consumer, on this, you're partly right! I see so many people say "Embargoes are the publishers trying to keep information out of the hands of consumers, they are inherently unethical." So let's have this thought experiment.
Imagine there's Jason from Kotaku over there.
Imagine there's me from Whogivesashit dot com over here.
Jason gets his copy of Goat Killer VI, the hypest game out there, on Wednesday afternoon. Since I am in San Francisco, I get mine the Tuesday morning before. The game comes out the following Tuesday. As Jason puts his game in to the PS4, he checks his phone and sees a GAF thread saying "WHOGIVESASHIT GIVES GOAT KILLER VI PERFECT 10!" So people are going crazy to click on this review and find out just how awesome this totally awesome sequel is because it is the only review out there. Jason, who takes his time to play the game and gets a review out on Monday morning, isn't nearly as happy with it. He ran into significant bugs, discovered the ending was half-finished, and the game is rife with microtransactions, none of which made it into my review. But no one cares about Jason's far better-written review because everyone already made up their minds when it got a 10.
Embargoes ensure this isn't a thing. Whether you get a game on the Tuesday or Wednesday, everyone puts it up on that Monday. Everyone has time to play it and no one is scrambling to finish it to get a review up first. For the publishers, this makes sure no one scrambles through a game and ignores all the good parts. For reviewers, this makes sure they have ample time to play a game and write a review without worrying they're doing damage to the site by doing it right. For the consumers, it makes sure we get the best possible review we can get.
Now, you might ask about release day embargoes and, you know what, that does suck. That is a publisher knowing you are so beholden to the preorder and hype machine that it doesn't especially matter when the reviews come out. And you know who you should blame for that? Not the reviewers who accept the embargoes (the only other option is waiting for the game to come out, so it's not like you would get the review any faster), you should blame the publishers. The way you solve that is by telling them you won't pre-order games anymore because you don't like that they're holding back reviews.
But then every Assassin's Creed Unity thread is filled with "Day one" or the Dragon Age 3 thread I saw the other day where someone proclaimed it to be their GOTY and they can't wait to try it, so I don't have a super high hope of this one happening.
There have been occasions where publishers have said they'll only allow an earlier embargo date for review scores past a certain threshold - usually a 9 or above. This does happen. You know who's never a part of those early review embargoes? Kotaku, Gamespot, IGN, Giant Bomb, etc. It's always the little guys. Even if they do give it a good score, they don't bother with those tiered embargoes and no one gives them enough credit for that.
The reason it tends to happen with Youtubers more often is because youtubers are small, they want hits, they want free things, and they feel like celebrities when publishers are paying attention to them. This isn't true of all of them, but it is the reasoning publishers use when they do pursue Youtubers for threshold embargoes and preview events.
Honestly, if Gamergate wanted to stand for ethics, they would pursue publishers' many, many problems. But it's not about that, because it's about journalism. But then it's not about that, either, because it's about women.