Replying in the DE thread since this is about AoE3. @tomchick
Like I said, they are getting ever bolder, ever more colorful with new content. It’s for you to judge whether that’s a good burst of creativity, or wasting ideas enough for five civs on one.
Swedes & Incas are kinda obvious: an aggressive civ with a house that auto-gathers for AoE3 veterans, a defensive civ for hypothetical AoE2 converts. The US just gets loads of new stuff, like immigrant cards in place of settler cards that let you mix-n-match other civs’ abilities, two cards as each age-up bonus, decoy Quaker Guns.
Then the African update is like a full expansion, adding over a dozen maps, some very powerful minor civ allies (which the two playable African civs can choose to ally with as age-up bonuses). African Livestock Markets make you keep cattle for their unique Influence resource (for hiring natives and mercenaries), or sell them for wood and money. Ethiopians are infantry-heavy and has the biggest mortar, while Hausa fields armored knights. Hausa Universities gain XP trickles from proximity to certain other buildings, and train Griots - bards who can switch between buffing units, buildings and debuffing enemies.
They have also added the Empire Wars mode to good effect, a sped-up game where you are constantly getting more resources. (The new maps & modes are free updates.)
This month’s Mexico boasts two unique revolution options for each age starting from age3, and allows you to return to Mexico after a revolution, which means seven options for each age. They even have a special Maya revolution exclusive to the Yucatan revolution in age4. The civ is extremely versatile in age-up options and two different heroes (a general & a healer), but less flexible in its unit roster such as dirt-cheap peasants armed with hoes and pickaxes, expensive strong musketeers, and Hacienda which is a combined econ building that can raise & butcher livestock on full-auto with a card.
To be fair, AoE3 was trading in the human wave stereotype of 20th century. The AoE4 bad-ass version is closer to history - for the majority of the gunpowder period, Russian soldiers were known for their toughness.