Generalised rating systems aren't really that great. Given how general they are. Imagine if a book is advanced Sci Fi, as in the concepts are built on exiting

Generalised rating systems aren't really that great. Given how general they are. Imagine if a book is advanced Sci Fi, as in the concepts are built on exiting and other well known scifi books. The normal reader won't understand and think it's terrible. The actual target audience, Sci Fi book nerds, would love it.