Probably wouldn't even happen, though.
It already has. Try Age of Pirates 2: City of Abandoned Ships

Or Pirates of the Caribbean with the Build mod, if you want Bethesda to have a hand in it.
Has anyone played potc with the Build Mod recently? Last time I tried it was a couple years ago, but it looks like it is still be worked on. It adds tons of new content to the game.
Last one I tried was Build 12, I think? I stuck with an earlier, customized build though. Smaller tweaks suited me better.