Reach 75 levels in three reputations to become a "Pirate Lord".
Not only does it give more incentive to do voyages, but it will also increase the PvP scenario.
The title, and a new set of clothing would be awarded just like when you hit Pirate Legend. Maybe even new equipment, and weapons. I'm sure all Pirate Legends can agree that sometimes loot isn't even worth hauling unless it has significant value in gold, Athena's rep, or towards an achievement.
At the very least make it a thing if the cap was ever to reach 100, and just have it earned at 100 in three reputations. I can understand that a lot of Pirate Legends are close to 75 and/or already are, so if a big patch were to come out players wouldn't be able to just log in and get it.
Also, please don't make the Pirate Lord outfit flamboyant and ugly. If it makes you say ARRR, then we're good.