If AH were to go two-sided the only quick way to do it would be to disable the missing country's fields on each MA map, as creating brand new two-sided maps would be a massive undertaking and special event maps lack the necessary strats etc. The disabled fields would still be there, just uncapturable and not accessible to players. So there would be no benefit to frame rates as we would be playing on the same maps.
Apart from the everyone piling into one country issue already mentioned there are other problems I can see that might arise from this arrangement. One would be players hitting fields and strats in the now empty country to get easy points. I could be wrong but don't think there is an easy way to prevent this short of editing the maps to remove all these fields and strats or HT writing new code to make that country's objects immune to damage. Also some of the less symmetrical maps might have balance issues without a third country in the mix.
