I think would help is a auction system at the ports and have PVP with PVE zones together ln the same game. Have safe point for your ship to dock for some silver and Gold which both should be in the game.. If this my game this is how it would start out. Have your character creation, then you pick your career Pirate, Trader, Adventure, what career adds extra perks in your skills. Then pick what nation you start your location at and you get a skin for your sail to fly your ship to sail under. England, Spain, China, and Pirate. I would break up the world islands into territory islands that can be govern and ruled by players. I think skills should be more individual and more precise. You can be a hunter skilling animals that give you types of hides and the more you get the better you become unlocking that skill. Then you can take you hides and take it to a trader for some coin. The Trader then might know that England Territory islands are paying a better price then the Spanish territory islands. And of course the Pirate's black market might be better. Territories can be at war with each other or have peace. Just some thoughts in how I would make the game work.