Ubuntu's popularity could mean more work *depending on how far Mir goes* for the Wayland guys in making things compatible.
..Just forking Wayland would've been an easier solution than making your own bloody display server
Also: "Canonical’s decision to keep development of Ubuntu 13.04 closed was also controversial. Although by releasing its code under a GPL license, Ubuntu remains open source by the Open Source Initiative’s definition, it violates the spirit of openness and transparency. Rather than working out in the open and accepting feedback on message boards — or code contributions through a system like Github — Canonical chose to work in secret, allowing only its inner circle to contribute. Some call this approach “throwing code over the wall.” It’s another sign that Canonical wants greater control over its open source projects." --http://www.wired.com/wiredenterprise/2013/03/ubuntu-mir/
The way Canonical is going: They'll end up makig some reason not to use the Linux Kernel anymore and make their own.