It's funny to me that you mentioned Ghost in a comment, because Ghost and Gutenberg differ in a really fundamental way that highlights the underlying flaws with Gutenberg.

Ghost stores all posts in a standardized JSON format, called MobileDoc. This means a standardized, parseable, extensible, and unambiguous data structure underlies their posts. It also means that that structured data can be edited by any editor that reimplements the MobileDoc standard (case in point, their WYSIWYG editor and their markdown editor both produce MobileDoc), and it means that all views are rendered from a single "data-first" structure.

Gutenberg, on the other hand, is using a custom data storage format, based in HTML Comments. This is a fragile system that is ill designed for modern parsers, and relies on a heavily abstracted complicated pile of regular expressions to parse.

The text editor just gets all this stuff thrown at it raw, and is therefore practically unusable. Not to mention we still have raw html support mishmashed in with wpautop.

Also, rather than smart rendering from a single structured source, feeds, excerpts, and posts themselves are a weird mishmash of raw and parsed data from this unstructured-structural mishmash.

Ghost is onto something, and is building a framework that can be easily replaced and improved, with good structural bones. Gutenberg is just throwing things at the wall, and hoping they stick.