"While I called this the most complex piece of the design, it is actually a simple thing to do with most page builders or with a few lines of CSS."

Has anyone ever given a good explanation for why Gutenberg didn't offer the option to adjust most CSS values of a box like other page editors and instead often opted for custom solutions to adjusments? At least as an option? I mean, it's basically what editor plus does (which you celebrated a lot) within the constraints of Gutenberg, and that was, I think, largely a one man show, compared to the team developing Gutenberg. So doing it the way it was done cannot have been due to the amount of work required, it should have/must have been a design choice (albeit one I can't see a clear rationale for).

Somehow this keeps feeling a little in-between, like the Admin interface experiments between 2.3 and 2.7. To me, Gutenberg still feels 2.5ish from a user as well as developer point of view.