The thing is, GNOME has always been an interface that's highly optimized for desktops and laptops. If they wanted to come up with a new interface for tablets and mobile, they should have done it with a separate project.
Do people honestly see long-time LINUX users dumping their laptops / Desktops for Tablets / Smartphones?
I really don't get the pull for "unified" interfaces. It doesn't make sense. I don't do the same things on my mobile devices that I do on desktop / laptops. Not. At. All.
There is no reason to Unify them. The closest thing I could see is similar interfaces, with features useful on both included, but otherwise different.