@Hitmuton, I mentioned in this thread that I generally agree that a five star system is not ideal. There was some back-and-forth in that thread regarding the merits and limits of switching from five star ratings. I still have reservations regarding any ratings system, but the fact that the stars are not tied to quality of a game, rather reflecting subjective enjoyment shows a conscious effort on the part of the the site management to address this issue., I think there has been an attempt to minimize ratings as a signifier of objective quality. Perhaps, as you mention, a favouriting option is useful. As was mentioned, and I believe also touched on by @peter, the combination of like and stars used by Letterboxd may be a useful model. Perhaps that provides better nuance.
However, even without a rating system I think there will be an effort made by some to provide ratings of their own. There’s no real eliminating the desire to rate a media experience. While some may be less inclined to do so, others will always gravitate toward using ratings as a metric for conveying a sense of their own experience, or gaining insight from others’ experiences to evaluate potential games to play.
I empathize with your desire to change the system, especially since objectivity is essentially impossible in respect to experience. However I don’t know if switching to a like/dislike system offers more nuance than rating systems. And since, as @kazooie points out, the star system is loosely attached to experiential or emotional view of the game Grouvee may have already addressed that issue. Perhaps part of the solution is making the meanings of those stars more explicit or visible as it is easy to miss out on their meanings (especially on mobile).
I am with you in spirit, given my dislike of rating experiences, but I am somewhat at a loss for identifying a solution that is not also encumbered by problems.