I think you have a misconception of what freedesktop is, it is not much more than a hosting service for desktop-related projects. If someone wants to submit an RFC there the process is the same as it's always been, other people working on that can choose to accept or reject anyone else's proposals. I wouldn't say GNOME or KDE or wlroots or any of those are being a main driver, the point with that is that they have to come together. None of them can just say "I am working more on standardization than you are," that doesn't make any sense when the participation is voluntary.

(And just IMO, things like layer-shell are not really a solution that fits with Wayland, that just puts us back in X territory where clients can position themselves arbitrarily, steal input and take over the screen)