I've noticed it too. One possible explanation.
This year brought us some real gems earlier on. Bioshock Infinite, TLoU, and GTAV all in succession. I know people going on about how those games "ruined other games" by being too good is eye-roll inducing, but I feel there may be some truth to it. Notice how many reviews focus on the narrative lately. Before, it used to be who gives a fuck about the story in games. Now, bad storytelling could potentially ruin the experience because new expectations have been set.
I'm not saying that all games need a good story now, I'm only using that as one sample aspect. But I think it's possible that in the eyes of many (including reviewers), a lot of games that would previous be considered acceptable now feel like cheap imitations.