Recently, I filed a bug (1274451) about running virt-manager on Wayland.
As it turns out that this is applicable to running gui applications as
root on Wayland in general, the scope was changed (see Cole's comments).
As Halfline points out, the decision needs to be made whether to allow
gui applications to be run as root. I figured I'd bring this up for
discussion in the hopes that a decision may be made whether or not to
allow this.
In the instance that the decision is made to not allow gui applications
root access, then we will also need to figure out a sane way to have
applications that require more than the usual set of user priviledges to
continue to work across multiple compositors and window managers that
may or may not have the necessary authentication agents built-in.
John.