Probably just be a much much harder 72 hour fate or hunt type thing where we can all zerg it down to get loot, since more than 18 people can attack a mob in this game.

At most you will need to actual know the mechanics and come with a party to live, but if it's open world everyone is gonna have a chance at the loot. So really wouldn't worry about it. And we already have some fates that are 36-48 timers, odin/ultima/coregula. Not much difference