Okay, so I can upgrade a warrior to a legion for 110 gold. Seems like a bargain, huh? Here's proof: Cost to buy warrior: 200 gold. with the upgrade cost, thats 310 for a legion. Cost to buy a legion: 400 gold. 90 gold cheaper to go the upgrade route than the buy route! Upgrading should be the more expensive option, or at least on par with unit purchasing.