whats the problem with having community guild heads? I'm pretty sure that the guild can have multiple leaders...
As far as i can tell with the press beta, the "guilds" aren't so focused in GW2, the way PVP works is there is three factions, red blue green i believe. You fight for control over strongholds and supply depots, then after a week, month whatever the eventual time is, the map will be reset, and according to your group's performance you will be moved up and down a ladder, who your group is paired with next also depends on the activity, so a group in the UK who are active 98% of the time 6:00pm to 9:00pm will not be paired with an american group, which are more active 1:00am to 4:00am UK time.
Whether or not groups of people are guilds, i don't know, with the few press beta's i have watched you could join any random battlefield and play with a random side, so possibly this World V world will have nothing to do with guilds?