Been iterating a lot on ease-of-authoring lately (https://twitter.com/pfrazee/status/1155221334106017792). On top of convenient editor tooling, I'm really interested in composing the UI so that people can get a lot out of value from very little work.
One of the simplest tools for that could be a "theme" setting which injects css and js onto the page, grease-monkey style. You author unstyled html/markdown, pick a theme for your site or page, and you're set: the browser imports css & js from the theme dat. With web-components declaring new HTML tags, you'll even be able to get widgets imported from the themes. <paulstheme-recent-blogposts>, that sort of thing.