Question on game balance in this setup

[Loren]

Maraxus said:
(A bit) More than 1/5 is not too unbalancing, too.

While the water nation is unlikely to be the first to die, it will also have a hard time winning, once the first two land nations fall and the remaining two have 1/2 of the land mass each.

Yeah. I'm rather new to MP, I'm playing a water nation. I've kicked one land nation out of the water, there's one other water nation that even if I took it out I couldn't hope to win. There's no way I could hope to build an adequate force on land.