Being as this is a TBS game lends itself towards makeing the support for PBEM straightforward.
One thing that must happen for PBEM to be possible is that the game support also a non-human-controlled tactical battles. i.e that it would be posisble for the AI to manage the player's armies in battles. Of course the game can support it in a primitive level or in a sophisticated manner with "smart", "configurable" and "adaptable" AI.
Being as AI is one of the strong points of stardock the 2nd piece falls into place. Making PBEM possible for this game.
I think it will do so much to enrich the game.