Loving the app already. It's like Anilist, but for books. So much more visually pleasing and nicer to use than Goodreads or even Storygraph.
So, why not take a page out of Anilist's book and add the option for a 100-point rating scale? Anilist lets users choose between multiple rating scales depending on how they like to rate things, including 3-point bad/ok/good, 5 star, 10 point, 10 point with decimal, and 100 point. This flexibility of rating is one of my favorite features of the site, and the primary reason I abandoned MAL for anime tracking. Similarly, being limited to only 1-5 stars without even the option for half stars is the primary reason I abandoned Goodreads for book tracking.
Some people will say that a full 100 points is overkill. That is probably true, but personally, I find 10 data points (0.5-5.0 stars) to be too constricting, and would really like at least 20 data points, so that on a 10-point scale, I could distinguish between a 7.0, a 7.5, and an 8.0. And if you are going to the trouble of implementing that, you might as well go all the way and let users pick arbitrary decimal points, turning it into a 100-point scale.
If implementing alternative rating scales is not currently in the cards, it would be very nice to at least have quarter stars, which would allow for my desired 20 distinct data points to rate by. StoryGraph already has this feature, which is the only reason I considered using StoryGraph instead of Hardcover.