I don't think there's much discussion to be had, open world PvP WILL destroy the social culture of FFXIV. It's certainly what ruined Aion for me. Imagine if you will going out on a leve and having a group of 50's camping the spot they know you need and PKing everyone who tries to come by. Imagine going out to gather and having someone come up from behind and kill you while you're mining. People can and will do these kinds of things often with an open PVP world, I saw it with Aion and it'd happen again with FFXIV.