I understand where you're coming from with that line of thought, but I still don't see it happening. If nothing else they have to know that they would risk tearing multi-nation LS's apart by creating faction based PvP. And full blown world PK just seems out of the question in this game.

I personally like PvP, especially full blown PK content in specific areas(ala Runescape 2002 Wilderness). I just don't see it working beyond either random PuG or LS based instances via something like Ul'Dah's Gladiator arena.