I have played many mmo's over the year's and the one feature that would perfectly fit in would be the Betrayal system which let's you swap faction.
It would require some changes since the eq2 main factions had underground/slum areas which you had to travel into and start earning rep with your new city before the guards would instantly kill you top side. Storm Wind would be easy since it all ready has a massive open space that can be used but rest would require a little work.
The fans of pvp might enjoy this also since at one stage of the quest line you end up being hated by your original faction so you become kos by everyone. If you wanted hardcore pvp then you could simple stop doing the quest line since exiles had there own little hideout.