First and foremost, Ubuntu 14.04 LTS on the desktop won't be Mir-based, or rather XMir. We've been wondering whether Mir will be used in Ubuntu 14.04 LTS after the XMir support was delayed from Ubuntu 13.10.
It was affirmed today that Ubuntu 14.04 LTS will still be shipping with the stable and proven Unity 7 experience, which is designed around using an X.Org Server with Compiz. It doesn't appear they will try for using XMir by default in this next Long-Term Support release with Unity 7. It was also said today that point releases to Ubuntu 14.04 LTS will not be adding in Mir or Unity 8.
Mark also said that Canonical is in talks with multiple companies about shipping Ubuntu Touch devices. However, there weren't many details given and any Ubuntu Touch devices are still likely several quarters out.