A lot of older MMOs have open world PvP. This idea on its own wouldn't work very well in 14 for about a dozen different reasons.
BUT! What about a dedicated zone for open world PvP? Imagine it works sorta like eureka. This zone has tons of things to do and quests and rewards etc. but you have access to your pvp kit and every now and then an event will kick off that grants extra rewards for pvping. Maybe even you can challenge other players to duals. Perhaps the zone gives armor and accessories that boost your stats when dueling other players. Thoughts?