Hello Linux Geeksters. As you may already know, Canonical has been working at lot at Mir, their own display server, which is intended to be an alternative to the good old X.org server. Initially the Ubuntu developers planed to use it as default on Ubuntu 13.10 Saucy Salamander, but the idea was postponed due to some performance reasons.
For now, the Gnome developers remained quiet about adding Mir support to the Gnome Desktop and Gnome Shell. Ubuntu 14.04 Gnome will be coming for sure with the X.org server and most probably, Ubuntu 14.10 Gnome also, according to this Google+ post.
Since Gnome 3.10 already got Wayland support to work on Fedora 20, the first Linux system coming with native Wayland support, Ubuntu Gnome will replace X.Org with Wayland, in the distant future, for sure.