> Elliptical gradients, font compositing with gamma-correction, seamless polygon joining, rotated fonts and images, pixel-perfect matching, etc.
These are supported in XRender. But even if they were not, it's always possible to extend it. For example older XRender version (more than 10 years ago) have not supported gradinets, gradients were added later.
But that's not important because Wayland has nothing like XRender, so in that part its worse than Xorg anyway.
> However, good OpenGL/EGL compatibility is necessary, because basically all videocard users need it.
You mix hardware and drivers support. Do you know why SNA works faster than EXA on the same hardware?
XRender is better, because it can be heavily optimized in drivers for the particular adapter. XRender is also better for users, because they don't have to manually check and implement all the GL quirks. Do you think that OpenGL/ES is just either supported or not? Some feature that you have used to on your video adapter can be missing on another one. Check "OpenGL extensions" section in `glxinfo` output. For XRender that can be done once in drivers, without it, i.e. in Wayland, you have to do that in all your programs yourself.
Wayland makes things easier for wayland developers, while X makes things easier for the rest of developers. Feel the difference. :)