When the numbers look like this, it's detrimental to gameplay. Unfortunately I've been imbalances on this scale a lot lately. Sometimes my country has the numbers (Knights), sometimes Bish do, sometimes Rooks do. I don't really care WHICH country has what numbers, but when one country outnumbers the others put together it messes up the arena.
I'm beginning to think that maybe it shouldn't be possible to defect to the most populated country if said country has more than +20% of the numbers of the next country, or something like that.
J_A_B (attached file should follow)