[kelnos]

> The transition to Wayland also seems to correlate with the adoption of client side decorations (CSD)

Not really. The GNOME/GTK folks were already on the CSD bandwagon well before Wayland. Wayland compositors are free to draw their own decorations (and xfwm4 will indeed continue doing that once it's a Wayland compositor), and one of the actually neat things about Wayland is that there is a protocol that allows the compositor to tell applications not to draw their own decorations. (Whereas on X11 an app can tell the WM it will draw CSDs and the WM can't do a thing about it.)

Certainly GNOME has gone all the way to CSDs (IIRC if an app on GNOME doesn't draw CSDs, they get no decorations at all), but that has nothing to do with Wayland.