In reply to Zebulan.

I'm not sure I understand your comment?

In terms of responsive design, it really isn't that hard to make that happen. It's just CSS. The hard part is deciding what options should be there, how those options should work, and how much control is provided to the user in the core blocks. Should there be predetermined breakpoints? Should the breakpoints be provided by the theme? How many breakpoints should there be? Should CSS Flex or Grid be used? How do you organize the features? What do the controls look like? What is the proper way to implement varied-width columns and how do those affect responsiveness?

If the devs tried to focus on that now, they would not be able to fix the more pressing issues of getting bugs fixed with the current features. I've already seen people complain about the devs focusing on stuff like fullscreen mode and spotlight mode instead of bug-fixing, which is funny since both of those features were introduced because of user feedback. As far as I can tell, the plan was always to have Gutenberg release in WordPress 5.0 with a focus on blog posts and a solid core that can be expanded to page building and soon entire website building in phase 2 and beyond.

But instead of getting information second-hand from me, which may be misinterpreted or miscommunicated by either or both of us, perhaps you should go ask the devs yourself or check out the existing handbook and various other documents that have been released. I'm sure they can explain things far more easily and more accurately than I can.