If you are not going to implement X11 drawing ops and XRender (which I, and many others, still use heavily), what's even the point? Any 'modern' program that only does client-side rendering already supports Wayland. AFAIK GTK 3 doesn't even support DRI on X11 unless you somehow trick it into using the abandoned OpenGL Cairo backend, but that's not modern enough apparently.
Where do they say they're omitting drawing and xrender?
If I could give a comment HN Gold, it would be this comment. 3 times.
We get the window management APIs back perhaps, unlike the eternally broken Wayland ecosystem.