Good idea, which could be implemented better. Designer & developer thoughts.

I understand, that a lot of work has been done, and maybe it is too early to expect something extraordinary from Gutenberg editor, but here are some thoughts.

1. It is too easy for clients to break page layout.
My main issue with the editor is that it’s not client-oriented. As a designer I don’t need any fancy editors, but for clients, who know nothing about design and coding, it’s way too difficult. Personally I hate pagebuilders for same reasons and I’m really disappointed to see some pagebuilder functionality is going to be included in WordPress core. If you allow such features as columns, they should be at least fully responsive, which most of the times means that they should become full-width on mobile.

2. Why not use Bootstrap?
It would be really great if all styles were be based on Bootstrap, which would make them compatible with a lot of themes. It will be very annoying to create custom styles for CSS classes used by Gutenberg editor.

3. Possibility to predefine text styles, like it used to be with WYSIWYG editor.
Currently there are only headings and S, M, L, XL text classes. It is totally necessary to have possibility to add custom text styles, such as lead, and predefined text colors. Disabling custom (numeric) text sizes should also be an option. I always strictly follow designed styleguide, so only certain font sizes can be used. In general inline font sizes are not good for responsiveness anyway.
Button styles should be definitely predefined by theme developer too. It would be weird to have buttons of every possible color all over the website…

4. Metaboxes
Most of the websites I create have a lot of custom page templates, which don’t use editor at all, but use custom metaboxes instead. It just cannot be done another way. As I already mentioned, I believe that clients shouldn’t have possibility to change design by themselves, as most of them know nothing about design. Therefore predefined metaboxes are the only option. At the moment Gutenberg pushes all of my custom fields to the bottom of the screen, which is not the right place for them. It would be really great if metaboxes were part of the editor. Ideally there would be a preview of the original page template with editable text and image fields in it, kind of live editor.

Cheers