Unlocking map parts for gold

You could essentially bribe some corrupt NPC guarding a passage to a new map or parts of the map. You would meet more experienced players there because it'd cost a lot of gold. The new islands could be in different biomes like artic, where your ship could freeze. Some special events could be happening only there, like teaming up with everyone around to kill some giant monster and then fight for the loot with others. You could gain access to special vendors that sell exclusive items... Sky is the limit.