I see problems with this. Players develop an 'affinity' to their nation of choice. Smaller nations will, probably, never have the manpower to "win" the game outright.
Frustration may lead to either players just leaving the game ... bad ... or jumping to a larger nation far a chance to be on a "winning" side, making the situation even worse for the smaller nations.
I love this game and the PVP, but am not into the scenario you have just announced.