I'm not saying it's not stable, I'm saying improve to the point where merging servers is a real possibility.
As for expansion? The world is the limit. North to do the coast of Canada, and South around Cape Horn to open up the west side of South and Central America. Over to Europe to open up battles in the English Channel, or the "Triangular Trade" routes. Even the Pacific - The East Indies. Or China - with few and far between ports - all Free, with amazing wares but huge investments in time to get there and no outposts.
It's the Age of Sail, this is when Empire became a global concept.