This is great. However, this kind of worries me:

“WordPress development just became very complicated with the Gutenberg project. I’m also not sure how devs will start writing extensions. Some users might expect them to keep the shortcodes for the old editor. Some might ask for blocks in the new one. Is there an API or back-compat? In short everything is changing and this change has both pros and cons.”

This feels like something that should be defined by now by the project leads. Not implemented but things like "is there an API, is there backward compatibility" should be known even if something isn't targeted as a 1.0 release feature.