The best you could do in WoW is try to set it up so they get killed by mobs and lose armor durability, that and sacking towns like TM USED to be fun until they carebeared the fucking PvP servers.
Up to this point, I didn't know DFO was being developed in Greece. Maybe we're going to see a lot of Mediterranean players with little MMO experience, who knows? I do know that every MMO has sheep, though. Not sure if you've ever heard of Xenimus, but it was an extremely small MMO I played for about a month after Trammel came out. At most, it had 200 players on a single server, with a world about 1/10th the size of UO's. At least 80% of the Xenimus population were Australians who wanted to PvE, and the game had full loot/PK just like UO. I know DFO will have a decent amount of sheep. If they don't, I find it 110% more enjoyable to grief a fairly good player.