Actually, I honestly think GA playing Switzerland may have been the most helpful thing to Zonasa/Kindara, due to how it shaped the front. If they had actually joined on our side, they probably would have been overrun my Arcaea reasonably quickly.
I think this about sums it up. Avoiding GA forced Northern alliance to move through Azros, Palanos, Haul, or lose 1/3 of the army to starvation through Leod/Edairn. Since GA's geography is almost completely indefensible, their neutrality likely was an advantage for us.