They said player housing would take several expansions. Maybe they can start in a patch where they can introduce player housing to Stormwind and Orgrimmar first, then spread it out to the rest of the world in another expansion. 2nd phase would be Thunderbluff, Ironforge, Silvermoon, Exodar. Then third phase they can update the old and introduce housing there, like in an expansion maybe.
Maybe first phase introduce a carpentry for the furniture first and current dungeons and raids. Then to time walking older dungeons and raids. If that's all too big in a patch, maybe a prepatch or beggining of expansion then add the later phases in patches.