I'm not proposing this, but posing a hypothetical. What if all the Continents were put on one map with existing realm with nobles in place with some shortish travel time in between continents and lastly a way for armies to travel further for longer.
I am mostly curious if realms on the same continent would band together to fight other ones, or if realms would try to find new allies from the other continents. I think realms would generally stick together with their continent mates at first until everything just felt like one map.