At the risk of straying off-topic: in the past eight years, most of Mike Paquette's concerns have been addressed:
1. Font server support for antialiasing, vectors, etc. render/fontconfig/xft
2. Drawing with PS-like path operations cairo; XRENDER
3. Dithering and phase controls moot: Apple has dropped paletted mode supported
4. Color calibration could use some improvement
5. Compositing COMPOSITE, DAMAGE, etc.
6. Affine transformations of windows Compositing window managers
7. Mesh-warps of windows Compositing window managers
8. OpenGL video playback XvMC
9. Performance Better drivers
Would it really have been all that much more work for Apple to implement the necessary X extensions?