-Requires the reviewer to actually own / play the game
-Highlights the amount of time played so you can easily filter out people who just dismissed
-Lets you know who got the game for free or reviewed the game in early access
-The magnitude of votes is shown which lets you know if it is a niche title or mainstream blockbuster
-Gives you a timeline of votes so you can see changes over time and see if there are any review bomb cycles happening
It's not perfect but I find it wild that people think there is any value in these movie review aggregator sites when you can't even verify if the person watched the movie at all and these guys can just spam votes. Worse yet there isn't any incentive for the site to change this since more traffic means more eyeballs for ads.
Well, maybe one more caveat: user expectations as they relate to the genre or company. One thing I noticed while browsing the hidden gems list* -- which have games with extremely high ratings -- is that there's a LOT of hidden object games on there. I think there's one cat series that appears like three or four times. And some more conventional genres like RTSes or action RPG's are hardly present at all.
I think this is due to expectations: people don't expect a lot out of a hidden object game, they're generally very simple, and a small indie title can easily meet those low expectations. Whereas a genre that has included many big budget titles, people have higher expectations, even larger, highly experienced dev teams have a hard time pleasing everyone.