After GW2->ESO->AA I'm really enjoying Black Desert Online's FFA PvP. Not only is it super annoying to have a tremendous number of assholes on your side, but you also don't get to really play with other factions. I also like that there is a fairly large player-base on one server in BDO. AA had a much smaller population and you saw the same exact people for months.
Factional PvP helps casuals who aren't able to join a strong guild and can't really fend for themselves, but it has a lot of disadvantages to the people who are going to play consistently enough to create a server culture for your game.
ESO had a lot of problems but the #1 problem was the player anonymization it had that was done for casual friendly reasons. To this day I don't see how you could create a real culture in that game.