[Seven]

Well as far as I see it non-limiting fights between players are limited to Elyos vs Asmodeans, which can happen anywhere in the world really, but will benefit players most if done in the Abyss.

From what I gathered, there are also certain quests that encourage players to travel through the portals randomly appearing throughout the non Abyss areas. So you should be able to run into the opposing race several times while questing, grinding or what not, and that should pretty much mean instant PvP wherever you are.

As far as PvP within your own race goes however, I don't believe you will or should be able to freely fight wherever you are, except for special arena like areas maybe. Otherwise, it seems there's a Duel system, which both players have to accept. I'm not sure if there are any penalties for not accepting or simply for challenging, but anyway that's pretty much the only inner Race PvP I can see in Aion.

It's sorta blows for me, coming from the free PvP, with the wonderful option of PK, world of Lineage II, but the concept here is different, and Duals sound way too 'carebear' to me.

So one of the main concerns I have with the PvP side of Aion at the moment is how inner-race conflicts are gonna be solved, since you can't simply resort to the primate way of settling disputes in this case.
Cross-race shadow alliances and other race's alts come to mind, even though not even that's going to be enough in certain non-portal-connected scenarios.
If it does come to the above, I think the RvR concept becomes a bit skewed, so I hope there are mechanisms beyond having to buy several accounts in place to prevent and discourage players from such acts.

Ken did mention that Stronghold economy's going to have a lot to do with the guilds overall charisma, since the race's player masses will ultimately decide if the guild's gonna be netting enough taxes in from holding it, or if they just want to take their business elsewhere.