In reply to Andre.

Your point about documentation is valid but as a developer it is not difficult to use the Inspector to learn the underlying markup and use your discernment to see what the best selectors to use are, just as you would when styling any other 3rd party applications.

The good news is in WordPress 5.4 the markup and CSS of the editor got a lot simpler, so you should have an easier time learning what needs to be done. If it's any consolation, I was able to rewrite the Editor Styles of my own theme for WordPress 5.4 in about three hours and now my user's enjoy a just about perfect live preview writing experience.

I was frustrated like you when I learned I needed to do a styles rewrite, but that was the kind of thing I expected to happen when I chose to support GB with editor styles and custom blocks. I am hoping not to have to do this again for a long time, and considering I first wrote my styles back in WP5.0 and didn't need to touch them until recently, I am optimistic about the longevity of this rewrite. That I will give GB team the benefit of the doubt for as the editor has overall been a net positive for my customers.

I have my own gripes about the editor and think I will have even more as it gets more invasive but as a longform post editor it has been nice to use.

Lastly, and I don't mean to pick on you, but I think that you having trouble with the "multiple environments" of GB/classic editor (assuming you are referring to meta boxes) is more of a reflection on you than the editor being bad.

If we took that same logic and applied it to responsive design we would still see most sites don't support tablet and mobile views because "they shouldn't have to," so why wouldn't we develop our theme and plugin features to work in any environment as well?