You don't take into account that other people may have different criteria for a computer game that yourself. We don't even have a CRPG definition let alone objective criteria by which to assess one so how can you claim what score is rational and what isn't?
Because what is and isn't rational is fairly easy to tell apart if you still have a grasp on reality. Which most people even here do have.
Games can be rated very objectively - there's always some bias and some subjective parts, but most things about a game have an objective quality to them that can be agreed upon.
And then you'll end up in a reasonable range of ratings.
Someone could make a claim that BG3, even if considered it a good game, objectively has major flaws and does not deserve a 5/5 so all 5/5 are not legit. Then only 4/5 and 3/5 are serious votes worth considering. That is absurd but it the exact same line of reasoning as yours.
That is only absurd reasoning if your assumptions are extremely flawed.
Why would you think 5/5 is perfection?
1/5 is the 0-20% range, 2/5 21-40% ... 5/5 81-100%. You can move some ranges around and make 1/5 and 5/5 smaller than the rest, but you'll always end up with all of the "star" ratings representing a range of quality.
But yes, I'd definitely prefer if the vote had specified what the range was actually meant to depict. Not a fan of small voting ranges, precisely because of inaccuracy.
IMO just make it a number field with percentages. Let people enter 0.0-100.0.
Clearly one can disregard production qualities like graphics and audio as those are superficial things only plebians care about and focus only on the important aspects of a CRPG like combat/gameplay and story/writing.
No, you can't just disregard major aspects of games. Graphics and audio may not matter to you personally (which I call BS on, you're just trying to make a lost case here), but they definitely matter to most people, including most professionals, critics and, well, everyone really, not just the plebs.
I agree you can/should weigh things differently based on your personal bias. But even then you'd have to take them into account for the average.
And while I agree you can disregard production qualities or you'd only end up with higher results for AAA, you cannot disregard objective qualities like a coherent art style, audio and atmosphere.
I also forgot the technical side, performance, bugginess, etc.