I agree with your general concern (I saw someone on Natively giving nearly all 5/5 ratings and thought “well that’s not helpful”), but I want to mention that there is another case for when people generally rating 3-5 out of 5: they are choosing books to read that they are likely to enjoy. For comparison, my average rating on AniList for anime is 8/10. Some people might see my 8/10 average and think that I’m not using the whole scale, but that’s not the case. I’m simply only watching anime I expect to enjoy, so I rarely have to give a series less than 6/10.
Personally, I have two problems with these descriptions.
- The voicing is inconsistent. So much so that I’m surprised a company like Goodreads hasn’t made it consistent by now. Ideally it shouldn’t jump between feelings by the individual (e.g. “liked it”) and descriptions about the quality (e.g. “it was amazing”). Personally, I’d say ratings are always subjective, so I think subjective descriptors such as “liked it” are better. (I’d replace “it was amazing” with “loved it”.)
- I feel like 2/5 should be “didn’t like it” and 1/5 should be “hated it”. To me, “it was OK” is way too positive of a statement for 2/5. For me, 2/5 books have some merit of course (otherwise it would get 1/5), but usually I think 2/5 books are less than “okay”.
Anyway, all that is just my subjective opinion. As you said, rating stuff is hard and everyone does it differently. And honestly, even if there were descriptions I wouldn’t change how I rate books. I think as Natively gets more users, inconsistent rating methods will balance out.