It would be great if they released a House Greyjoy that not only comes with their core army but as well with rules for a sea warfare game mechanic. So you would also have a double sided board, one side sea, the other a shore line. There would be tiles such as, islands, harbors, docks, fortress islands. And most importantly ship models for all four of the existing houses currently in play. Each house would get their own navy: War galleys, corsairs, transport ships, etc.
Of course all of this is wishful thinking, hoping that the game is not abandoned of having future products.