On Ubuntu, we’re committed that every desktop environment perform well with Mir, either under X or directly. We didn’t press the ‘GO’ button on Mir until we were satisfied that the whole Ubuntu community, and other distributions, could easily benefit from the advantages of a leaner, cleaner graphics stack.
We’re busy optimising performance for X now so that every app and every desktop environment will work really well in 13.10 under Mir, without having to make any changes. And we’re taking patches from people who want Mir to support capabilities they need for native, super-fast Mir access. Distributions should be able to provide Mir as an option for their users to experiment with very easily
– the patch to X is very small (less than 500 lines).