As you may know, Unity 8 is Canonical’s next generation desktop environment, currently used on the mobile version of Ubuntu only, along with Mir.
While it is still under development, the developers being focused on porting Unity 8 to the Ubuntu Desktop. Most likely, Ubuntu 16.04 will be the first system to bring Unity 8 and Unity 7 by default.
Right now, Canonical is working testing the ability to use Scopes written in JavaScript, the thumbnailer has received some speed and reliability improvements, hotspot support has been added to the network indicator and a few other under-the-hood enhancements have been done.
Despite the fact that it’s still under development, Canonical’s Michael Hall has proven that Unity 7 is looking more as desktop DE with every day that passes.