The ability to use Gutenberg blocks on Post type Archive pages, both before and after the entries' loop and better handling of post type archives in general. For example, a simple thing that I deal with often is that you cannot allow the site Author to set/change the archive title unless you make some custom field and modify the template.

Maybe a good first step would be to extend the admin option that allows you to choose a page for the "post" post type, to the rest of the post types.