It's the lack of network transparency which is the problem. No one's complaining about the overhead of it, because Wayland lacks this crucial feature.
Edit: Other features lacking in Wayland: A close button which works, consistent decoration across apps, efficient cut and paste, ... And things which Wayland has that are basically bugs: windows which are rotated at non-90 degree angles.
It's the lack of network transparency which is the problem. No one's complaining about the overhead of it, because Wayland lacks this crucial feature.
Edit: Other features lacking in Wayland: A close button which works, consistent decoration across apps, efficient cut and paste, ... And things which Wayland has that are basically bugs: windows which are rotated at non-90 degree angles.