As a regular end user, I don't care where this is handled, as long as it is handled.

Network transparency is, to me, the killer feature of X11. I am aware that security on X11 is atrocious at best and that a replacement is needed, but any successor without network transparency is inacceptable to me.

Worse, actually, there are a number of other Unix systems (and even non-Unix systems) around that speak X11. In fact, the killer feature of X11 is cross platform network transparency. Unless other platforms adopt Wayland or a common wire protocol, that is lost, too.