Copy all content has been in the post/page editor for years now. Transparency for colors is way overdue--various third-party block libraries have it where core blocks don't. Determining post featured image size via the site editor is welcome.

Looking forward to additions to the site editing UI (e.g. exporting theme.json or creating new archive templates) and especially to a more flexible query block. As far as I can tell from looking at the roadmap, things are going in the right direction.