If the two continents are linked by trade and travel is possible, it's really not that different from old Strategus. NA clans more or less were a big, isolated land concerned with its own internal affairs in the previous Strategus. Like someone pointed out the possibility of a war between NA and EU landholders was slim since any invasion would easily be repelled by whoever was the defender and chose the server. The interactions were limited to diplomatic relations and mutual defence treaties. If anything with the implementation of trade the interests of the different timezones will have more opportunity to converge. If my supplier of a particular good (say, iron or whatever) across the sea is involved in a war, it could directly affect my own capability to defend myself, or support the economy of my holdings. Depending on relations with the supplier and the direction the war is going, you could work out a deal with the invader to continue the trade after conquest, or send troops, weapons and armor to your supplier.
As it was the NA clans felt that they had to band together in one megablock to counter any possible threats from EU clans looking to expand and it was just a stalemate for the duration of the game. Giving NA the chance to have their own intrigues and wars with their own continent, while still being relevant to each other through trade and diplomacy sounds better. There may not have been enough NA clans and players to justify it when Strat was just launched, but it was also said that NA now has a lot more clans and players. There's always going to be a divide due to latency anyways, may as well manifest it literally by having two linked separate continents.