I think it would be very useful to have a collection of UI components for plone. This becomes very useful when designing new views and backend interfaces.
In general, there isn't really a common standard for designing a control panel. I have more to say but just dropping a not here.
This is more of a UI Kit for UX designers.
It would have predesigned components that they could bring into their mockups.
The benefit is that they could quickly mockup new visual layouts using representative elements that align with "Plone standards". I put standards in quotes because I'm not sure that we have UI standards defined.