> Why in the world should that apply to fliers, though?? They aren't in the water to be slowed down!
Quite few birds cross oceans. They need to land and eat. Imagine a turkey crossing the Atlantic
In earlier iterations of dominions seas were generally larger as well. So it is also a survival from these primal oceans that makes them uncrossable and restricts movement. With the deep seas added some movement restrictions should perhaps be removed, particulary regarding sailing.