> It forces some kind of modularity.

Wayland is the complete opposite of modular; that's why the compositor has to handle everything. The claimed problem with X11 was it was too modular, easy for different clients to control various aspects of the environment, but perhaps too easy, lacking a security policy framework to limit client access. (Or at least a framework that was fully baked. Wayland put an end to such initiatives.)

The lack of modularity in Wayland has been widening the rift between the desktop environments. It's as-if KDE and GNOME each forked X11 and went their own ways.