I love that the OP made this app for themselves, enjoyed the result, and shared the journey, so that we could all have this convo. With that said, I feel that you've done what this "should have been" IMO. It doesn't have flashy spring motion scroll, but it does interactively capture what I'd care about, which is recording whether I've read the book, what I found relevant/important/memorable, and how it connects to other things I've read/thought about.