Battle Royale Kappa
My suggestion to add content are Open World events, similar to the last known fleet location thing we already have. For Example a Treasure Fleet. How does it work? First of all there will be a global message (like the last known fleet location) which says something like "Treasure Fleet sighted in Hispaniola" (Hispaniola is just an example). This is when the event starts. Now somewhere in Hispaniola an AI Indiaman with damn good loot sails around Hispaniola and has an escort as a fleet (maybe as strong epic events AI or reinforcement AI). When someone tags the Indiaman into battle, the battle wont close, its open for ever. Like the reinforcement zone there is one big join circle with 2 sides Attacker and Treasure Fleet. Green on Green is allowed in this battle. The Goal is simple, get the loot from the indiaman and escape. I could imagine an Event like this would be fun and not to hard to implement i believe.
I think Open World Events in general would add much more content, since it manages to bring players to one specific place and will provide PvP content.
One time i had one of all fish in the game at once . Maybe make something craftable which requires having all the different fishes. I would love to see "WTB Catfish" in Global chat