Good questions. I belong to a gaming community that has a lot of members and when we seriously decide to take our family (yup our community is a family, not a guild) into a game we can easily have 1200 people show up on day one. We did this in one game with guilds with player limits of 500 with no alliance chat and well the family felt all broken up no matter how we tried to organize the guilds to have similiar player types in them and of similiar time zones. It was a NIGHTMARE! That including the usual burps, hiccups and what not, including shiny newness wear off, the number of players in the game shrunk a LOT in two months.
I'm not sure how the community will flock to this title at this time, but there definitely has to be things not only to handle the solo player with no friends playing to the HUGE gaming communities that come with a troop of 1000 and want to be able to have ease of in game communication to ALL.