Originally Posted by
choom
Remix the old-school Faction Reputations and apply it to world-hostility and world PvP.
Every reputation, even something like Stormwind or Ogrimmar, could have an option to denounce. Basically resetting your reputation with them to neutral, which means you can also initiate combat with guards of that city. So, you could be a Night Elf who is Hated with Stormwind and basically treated as Horde whenever they step foot there.
The only limitation is that you cannot denounce your own racial home faction. So you could not as an Orc denounce Orgrimmar.
On top of all of this, player-to-player PvP status and hostility would be based on one-another's faction status. So, a Goblin whose reputation with Orgrimmar is hated, would appear PvP-enabled to Orc characters.
This would allow servers and communities to draw their own faction lines wherever they damn well please. It could make for some emergent gameplay in the form of emergent player factions.