Well, as long as there are more than two realms on the island, one is always going to get ganged up on by the others.
So I've wondered how the war would play out if there were only two realms instead of three. For instance, remove the city of Ikalak and replace it with a Toren-esque stronghold, or just remove it completely. Then you'd have Taselak and Sandalak, relatively close to each other's capitals, but with large swathes of useful land further north. You might end up with a more dynamic war too, compared to the typical "SEND ALL THE TROOPS TO THAT ONE PLACE!" battles. Fighting in the north and south would happen simultaneously.