A blackout to other reviews before writing your own is good, but a complete media blackout is not. Understanding the game and the vision / ambition behind it is important. A good reviewer need to decide how to judge a game before judging it. Knowing the design choices, which was executed well and which was not, how those choices contribute to the overall game design. For example, you shouldn't consider linear design as bad in itself. But you should judge how well it served the story and the level design (like in The Last of Us), if the story and level design were bad then linearity was indeed a bad choice. Of course, you can have an opinion about open world would have served the overall experience better, but that doesn't make what the developer tried to achieved is bad.
Other example is FF XV (not reviews but still..), criticizing having all male characters with an obvious lack of understanding of the point behind it.
