I think the team-sizes are fine the way they are.
Many smaller nations will have little trouble fielding 8 players, but increase that to 10, and you're decreasing the chance of a small team to field the minimum numbers by a relatively large fraction. 1/4-1/8 times harder, I should think.
And when you do that, you increase the likelihood of a default victory.
Anyways, this whole thread is redundant, because if both the teams wish, and have the numbers, they can go up to the maximum.