I was thinking that you could upgrade your gun or sword to prestige 1-5 and when you get to 5 you get a random power from it that might give you a special move. For example, Someone might get wave whiplash as the random power and they need water to use it. When they use it the opponent is knocked back like getting his by a wave. Or a lighting move where the sword points at the sky then can shoot a strike of electrity at someone.
And I Am Remaking my other post add something called skull enhancements. You find them on islands and there is only 1 of that certain enhancement every server. And you can either leave it on the ground but as soon as you pick it up you get the power to stop people from collected and hiding them. One of these skull inhancements could be called A pirates will where when you are under 10hp you can heal back up but it has a 5 minute cooldown. Another one could be called a hunt for gold where you can track every ship with treasure on it reapers flag or not. Some of these dont spawn in every server and they might be rarer than others. A rare one might be called reign over all where the players fist turns to gold and they can shoot gold or punch people with a gold fist which would do more damage or something names let everything burn where the player can shoot fireballs and turn there body into flame at will or a enhancement that allows the user to see the users inventory and how much health they have. This could encourage people to fight at islands that have these skulls and make more ships allowed in a server. I also reccomend a bounty system where you can put bounties on other players. The skull enhancement could also work where if you die the skull is placed on a random island and you cannot get another one for a certain amount of time. A skull enhancement that might be the rarest would be called something like spirit of the king of the pirates where they have the ability to control the seas in their favor. This ability could only be used once before it goes away and only have 1/100 chance of spawning. The ability could be used to spawn in a treasure or spawn in a kraken or boss to kill another crew.
The game should also have in server events that encourage players to come together. An example would be like a sea war at a certain location and could give rewards like 50k gold to split in the crew or skull enhancements.
These could encourage players to engage in pvp instead of hiding and fight for their rights of being a pirate in the world of sea of thieves
(I TOOK INSPIRATION FROM ONE PIECE ON THIS)