Harsh isnt even the right word..... to express how silly that score is, its worse than "harsh".
You can’t mandate a standard for something based entirely on opinion. There’s nothing that says an indie game or cheaper game should be reviewed differently. There’s nothing that says an exclusive should be reviewed differently than a multi platform. Some outlets do that, some dont.
When you say a certain score should only be reserved for certain qualifications you’re speaking purely from personal opinion and bias. But those are what makes criticism interesting. People reviewing are also applying their own opinions and bias. You seem to want a vanilla, standardized form of reviewing and that sounds incredibly boring to me.
Also, I disagree that a big budget AAA title can’t be scored a 3.5 because it’s not an indie title or it isn’t buggy. The Order 1886 is a great looking, fully functional and bug free title. I wouldn’t bat an eye at a 3.5 score for it because the things it tries to do well, it fails miserably. I haven’t read the 3.5 DS score and probably never will, but if the reviewer found major flaws with key elements then why can’t it be a 3.5?
Also maybe if you feel this strongly about scores, don’t rely on a review aggregator? Or don’t even look at them. Find a stable of reviewers who share your opinions and bias and score standards and only read their reviews.