Separate Post Author Avatar and Post Author Bio blocks are planned. When these next two land, it will give theme authors more flexibility.

Instead of making tons of individual blocks for this sort of thing, it seems like it would be better to create systems for using site/post metadata within existing generic blocks.

If you could just insert text metadata freely (maybe as an inline element?) then any functionality added to the paragraph/heading blocks by WP core or theme/plugin authors would automatically be available to use with the site title, post title, excerpt, date and anything else.

Along these lines, right now they are having add special-case options to use a post's featured image inside every block that accepts an image (issues for Media + Text and Group/Cover). It would be much cleaner if you could just select the featured image, author image or whatever else as the source anywhere any block accepts an image.

(I'd also guess this same problem has or will pop up for link metadata like the home page, posts page, and category landing page.)