add a few ports in game that are controlled by pirates only, that has no government or tax income but instead have increased sales for trades good. the ports would be open pvp/ plunder for any fleets that are heading to that port and none pvp/plunder for fleets that are leaving. no goods can be bought at pirate ports only sold for double the price for double the risk. this would add more for pirates and traders who love to take risk.
2nd option add challange port where a player can make a staked battle only at that port. like a battle arena. player setups up the battle rules. what ships can be used what lvl's how much gold to wager and so on. then other players can accept or make there own tournament. it would cost ea player 10 turns to use the arena and the game would charge 10% of the total wager as a fee from the winner.
-1 Skyhawk