Adam had the following to say on the mailing list:
Well, the Fedora graphics cabal is basically me, Kevin Martin, and Dave Airlie, and since we were hanging out at Plumbers last week and talked about this, here's the rough consensus I think we reached:
Wayland's not a usable default yet. It'll probably be packaged in F15 as something you can play with. We don't even have a complete list of transition criteria yet, let alone a timeframe for switching the default. But it's likely to happen eventually because it's a serious win for a lot of things, and the downsides are pretty negligible despite the fear from the peanut gallery.
So eventually, Fedora will switch to the Wayland Display Server.