I think that the switch will happen when somebody advances Weston (or any other compositor that has a single-app full-screen mode) so that running Xfce on Xwayl

I think that the switch will happen when somebody advances Weston (or any other compositor that has a single-app full-screen mode) so that running Xfce on Xwayland on Weston becomes possible and indistinguishable from Xorg.