This is an excellent idea. Decluttering the editors’ header after all the new GB icons that were added in the last few months (and to separate them, I think that’s important for UI and UX reasons) needs to be done in some way.
On the other hand, the user gets forced to use the quick inserter, unless this is optional.
Also, does anyone really use the pseudo state dropdown menu in the header?
Not sure, but why would one travel all the way from the block inspector and then back again?
There is a dependency of applying styles with the block inspector and making use of pseudo states.
To make it more clear to the user, the pseudo state icon in the block inspector could be swapped with the pseudo state menu from the header (text instead of icon approach).
What I also think is that the scale options/values should be visible at any time and not be hidden inside a modal.
It’s not only a scaling tool, but it also provides information of the actual canvas size in pixel, even when not scaling.
I know that it’s a matter of space though.