Hi,
I agree that when every plugins has its own GUI, WordPress admin becoming bloated, the experience is consistent, and somehow quite invasive (emojis on admin toolbars, custom notice with gifs and animation everywhere etc).

But the thing is that even WordPress isn’t consistent with itself: Gutenberg and Customize page are next gen, but the media uploader page ? A single black line on a grey background with a default box?
It is obvious that Automatic is letting down some parts of WP admin. It could be way more fluid, use more ajax(lot of pages reload feel unnecessary, lots of plugins needs to be installed for simple admin tasks like having a fields here and there), less pages etc. I wish they switch a bit from site building a come back a bit to the actual core of CMS: content management (aka, admin pages).

This is why plugin dev make their own things. Not ideal situation.

Some plugins dev succeed to make good custom UI which doesnt feel too different like ACF. I don’t use Yoast but it is surely a good occasion to open the discussion about more advanced UI elements API for admin for developers.