I've always thought it would be interesting to have different terrain based on the different original country territories.
So, if it's MMesa for example, one country starts on snowland, one on the desert, and one gets the tropical tiles we have now. Will rotate of course each map reset, and on each different map. Just provides a little more immersion...you "know" you're in enemy territory because of the terrain. Or, if the enemy has captured a lot of your bases, you have that reference point for a counter attack ("at least lets recapture snowland, guys", or something like that)
I think you'd see some more spirited base defense, as the concept of part of the map "belonging" to your country is a little more tangible than "oh, was that one of our initial fields? yes? no?". Which in turn would be great for gameplay.