Hahaha the Wayland that is done, that is version 1.0, released, the greatest thing ever so good it's not in any distro since nobody deserves them, couldn't minimize? Sure, Wayland is complete...riiight...
The 1.0 release was to mark that the Wayland protocol and API was declared rather stable so that developers could start working on their software and not expect it to break every new Wayland release.
As I understand, Wayland has come pretty far.
What remains is improvements to the Wayland backend for GTK and Qt, and also XWayland.
GTK's Wayland backend is probably getting in pretty good shape for GTK 3.8.
XWayland is a bit unstable and needs work.
Many applications needs to be ported from GTK2 to GTK3 and from Qt4 to Qt5.
Many applications needs to stop using X11 calls and not rely on Xlib.
Mir still has to do a lot that is already done in Wayland, in addition to getting support added to toolkits (which is mostly done for Wayland), waiting for those apps to be ported to (or compiled with) versions of those toolkits which support Mir, and making apps less dependant on X.org (which, thanks to Wayland, is already in progress).
Now look at Mir's todo list and say with a straight face that Mir has less to do than Wayland before it's finished.