Note: if anyone wants to build this, I would be happy to offer direct feedback.

Ha, you may get your chance to make good on this offer! I'm coming at it sort of backwards, in that I've build (and continue to build) WordPress tools to create book+ experiences in WordPress. Since you have to enter the stuff into WP to get the book actually there, I've started to think about what it would take to create a professional writer experience within WordPress, some sort of mixup of Word features, Dabble, Draft, and Scrivener... not working on it yet, but thinking about it in a fairly detailed way at this point.

Anyway, agree that WP blocks are more of a designer thing, for sure. If you're writing something complex and long, you need ways to keep an eye on the overall structure and the option to drop to a completely distraction-free immediate writing experience.

Appreciate the post!