Speaking of which, how many unique traits could one get on a unit? Lets say someone was able to run an epic team game and gifted a unit to one of his teamates each era.
Jaguar/Maori Warrior -> Mohawk/Legion -> Berserker -> Norwegian Ski Infantry -> French Foreign Legion -> Mech Infantry
= Units who can heal 2 hp, move through forest quicker, (not sure if the forest/jungle bonuses would stack, but if so like +75% in jungle/forest) or + 50% in Forest/Jungle and ability to build roads, 3 movement unit for the era and ability to pillage without losing movement and amphibious promotion, double movement in hills/snow/tundra and +25% in hills/snow/tundra, +25% in foreign lands and ignores ZOC, = The biggest beast of a unit ever?
Same thing could work I guess for slinger -> cho-ko-nuh -> norwegian ski infantry -> french foreign legion -> Mech Infantry