I read a while ago that Canonical plans to develop their own xwindows replacement for Ubuntu. Given the long and difficult struggle that the X team has faced over the years in bringing their project into the modern computing era, I'm not entirely against that effort.
However, I also know that members of the original X project have started their own modern version of a replacement (Wayland) that seems to fulfill all of the requirements Canonical is complaining about in X.
So, the question then becomes, 'Why is Canonical attempting to reinvent the wheel with no significant differentiating factors?' It stands to reason that they could leverage the work put forth in the Wayland project. It seems unlikely to me that Canonical would not have known about the Wayland project.
Given what Canonical did (or failed to do) with Unity, I'm skeptical that their new project (Mir) will be any more successful. I'd love to hear your thoughts on the matter.