In every game I've ever played where there was two factions the game was unbalanced after a time, and in some cases just became stupidly so. With people on the winning side quitting as it became too easy, and people on the losing side quitting as the mechanics didn't support losing in any way. It was very rare to have a neatly balanced map. Most people go to the winning side and that was that.
It'll be rare here too, but much more dynamic as a result. To put it in very basic numbers its not 1 x 1 x 1, its 3 x 3 x 3 for the amount of variables present.
Health bonuses helped in the original PS for instance also, and you had a term phrased as the unofficial 4th Empire, which were those who switched between sides often enough to benefit from those bonuses, or just to even out empires.
If you have a game that supports winning, such as PS2 looks to be, the effect is cumulative, people want to win and the masses move to or stay with a winning side. If you have a game that supports fighting more than winning, it isn't such as issue.
From an infantry grunts perspective if its anything like PS though what you'll see here, is good regiments swinging whole maps and believe me you'll know when it happens, you'll get about 20 seconds warning in chat saying such and such is on the way (if you are lucky) and them boooooooom
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