I've to ideas. The first: when I add a new book I think maybe more usable if it will open directly the editing page of this book, so users may add status (in reading, read, ...) or the review directly.
The second idea: "review permalink". Every book I read I write a review and I'd like to much to share it to my contact or on social networks. By now, reviews seem to not have a permalink or a sharing link.