In reply to Alex M.

My "gripe" is more about documentation or lack of as it relates to theme development for the back-end editor. Also, using the inspector to view markup does not always work well without doing some hacks. Regarding multiple versions, I don't make multiple themes for each, I integrate it all into one theme to cover the classic, block, and plugin versions. I even give the user the option to disable the GB stuff to lighten the load. As a side note, I even make the themes compatible for ClassicPress. Basically, many environments rolled into one theme.