Unity 8 Desktop Still Planned In Time For Ubuntu 16.04 LTS
While much of Canonical's recent focus has been about reading Unity 8 for mobile devices, their plan is still to ship Unity 8 by default on the Ubuntu Linux desktop ahead of its next LTS release.
Their plan for a while has been to use Mir by Ubuntu 16.04 LTS on the desktop spin along with using Unity 8 to replace Unity 7 + Compiz + X.Org Server. Will Cooke, the team manager of the new Desktop Team at Canonical, did a guest post on Michael Hall's blog to reiterate these plans.
For Ubuntu 15.04 the plan is still to use Unity 7 by default while Unity 8 / Desktop-Next will remain an experimental option. By Ubuntu 15.10 though they might be ready to potentially offer Unity 8 as the default while regardless at least through Ubuntu 16.04 LTS will be support for Unity 7 as an option. Ubuntu developers are taking their time at this go at the Linux desktop to ensure they nail it right along with their convergence strategy.
Among the advantages talked up for Unity 8 with the new Ubuntu Desktop is decoupling application updates from OS updates, application isolation, and a full SDK for writing Ubuntu apps.
Find more via Will Cooke's blog post.