Modular X.Org 7.0 is now stable on x86 and amd64. On architectures not held back by binary drivers, X.Org 7.1 is expected to go stable very soon.
Please see the migration guide for details. The main problem people seem to hit that they can’t figure out on their own is XKB breaking because of major configuration changes.
If you have any issues or want more packages keyworded stable, please file a bug. I’ve only marked stable a minimal set of packages to try to discover which packages people use.