I think it would be quite cool if some new maps were introduced.
Maybe some Historical wars Like WWII, the American independence war, the Napolionic war with naval territories, or the British Civil war.
These might be even better if they were made into two player games, So you could have the Allies and the Axies for example. In the case of WWII you could also make it a game of survival for the Allies at the Begining until the Americans join. You Could Maybe Make a WWII in Europe map and a WWII in the East map.
Lots of ideas there but really i think some maps with some Historical input might be really good.
Thx:)