For 10 men and I, I see one of two possible strategies. Either we should be placed against our predicted STRONGEST opponents (in this case, air/earth/entropy), to give us the best chance of beating them with more upgrades, and keeping them from getting too far ahead in vault count, or we should be both placed against our predicted WEAKEST opponents, to give us the best chance of potentially knocking them out of the War entirely. (in this case Light, and then the rest are tied)
For everyone else, I don't see it particularly mattering where someone is assigned, unless they have a preference/skill for a certain playstyle or a lack in their personal card collection for the deck we want to use in a certain match.