What's good about Wayland, is each compositor (window manager) can do what it wants, regarding how it operates and in its own styles of governance. There's XWayland which is intended to allow X applications to run on top of Wayland.
Furthermore, XWayland compatibility depends on the compositor, as newer compositors dropped that feature. Older compositors, like Weston have XWayland, but it may be primitive or faulty.
An upcoming compositor can set its own rules, and have a compatibility for XWayland, that uses newer implementations of libx11, that have libxcb underlying it. Wayland is supposed to depend on the graphical toolkit, rather than let programs not interface directly to Wayland. XWayland is an exception to allow legacy applications to run. It seems xlib programs will go the direction of XWayland on top of a specialized compositor and Wayland. I suspect the norm will later become a compatibility layer of X on top of XWayland/Wayland for select compositors, and it will operate like X.
As for Gnome itself, I stopped using that over a decade ago. Later switched to XFCE, then JWM. Finally on to MCWM, which is lighter and accomplishes what I need. I see use of gtk implementations being still in use, but not really of Gnome.