All this talk abbout unit exchanges had me thinking the other day, and an idea popped into my mind: ancient-age warfare is basically glorified rock-paper-scissors: axemen beat spearmen and lose to chariots, spearmen beat chariots and lose to axemen, and chariots beat axemen and lose to spearmen. Conveniently enough, we are surrounded by the rock, the paper, and the scissors. War Chariots will beat Dog Soldiers and lose to Impis, Dog Soldiers will beat Impis and lose to War Chariots, and Impis will beat War Chariots and lose to Dog Soldiers. With Fast Workers, we have the bargaining power we need to acquire any of these units. If we negotiate with the three teams, we could have an arrangement where we end up acquiring all three units.
This makes an even more powerful bargaining tool. If we can subtly show our newly-acquired units to the teams whose UU we can beat, this may reduce their appetite for attacking us. If we show off our shiny new Dog Soldiers to Spanish Apolyton, for example, they will think "Oh no! CFC has allied themselves with WPC, and has gotten Dog Soldiers! If we attack them, they will be able to beat of Impis!" This logic will apply to every team, and the hopeful end result is that none of them attack us out of fear of the other guy's unique units.