It would be awesome to exectute naval battles, and even cooler to play a pirate!
Maybe when Bethesda makes an ES game in Hammerfell...
There already are pirates: In Oblivion around Anvil and the IC docks, as well as in the game TES Adventures: Redguard (Which is set in Stros M'kai in Hammerfell).
There are Pirates in Skyrim as well. There's a quest from the East Empire Company that involves you getting rid of some.