Any user can already add genres and moods (and content warnings); if you open the reading popup for any book and click on "Genres, Moods & Tags", you can tag the book with whatever you want for each option. They then show up on the book's page with the most-tagged ones listed first. Librarians cannot forcibly alter this data. It's community sourced.

As for page count and other concrete book data, you can always use the Flag - Report a Problem option to bring inaccurate data to the head librarians' attention, or bring it up on the Discord server if you've joined it, or even apply to be a librarian yourself.

Agreed - I have come across so many books without page counts, missing descriptions or books that say they’re planned releases when they’ve been published for ages. I find myself going to goodreads for this info