Wayland on Fedora as default has been eluding us for a while now. Experimental support for Wayland was added in Fedora 20 but X11 still remained the default display server. The weekly FESCo meeting approved the Wayland Fedora 21 changes among other Fedora 21 features to continue the works on replacing X11 with Wayland.
Wayland couldn’t make it as the default on Fedora 20 as there’s still a lot to be done around the desktop infrastructure like port packages and switch APIs like gnome-settings-daemon and gnome-control-center. As a matter of fact, X.Org Server 1.16 is also expected by the time Fedora 21 is released. It will integrate basic XWaylad support to run X11 applications on Wayland without the need of any separate X.Org patches.
The main focus of Fedora 21’s Wayland support will be to address user-visible regressions and fixing limitations of GNOME on Wayland with respect to GNOME on X11. The end result will be an improved and polished GNOME Wayland session experience. If the work remains incomplete by the planned release time for Fedora 21, which is no earlier than mid October 2014, it won’t be a blocker as switching back to X is always an option. So it’s not sure that Wayland would be the default but it would surely be in better state.