Valahogy igy. Kis csipegetes:
This is not a 'weakness' of Wayland, it's a weakness of gparted (and other graphical applications that try to run as root). gparted should not run its UI as root. It should run its UI as a regular user and use PolicyKit or something else similar to gain elevated privileges only when necessary to query or modify devices. Many graphical applications have already been written along these lines. Doing it is not rocket science
There's no reason at all you can't write a graphical installer that works with policykit. This is, after all, precisely what GNOME Software is. It makes the software more secure, more flexible, and nicer for the user to use.
it's a perfectly well-understood situation. gparted needs to be rewritten for a Wayland world, there's really not much more to it than that.