Other across-the-board tweaks impact on all three civilizations. The biggest of these is the new Export resource. It is collected automatically based on a percentage of the traditional wood, food, and coin, and is then utilized to order help from European allies. Store up enough Export, build a Consulate, and you can soon be whistling up armies from the Dutch or English, or buying units and weapons. What's more, foreign armies count as just a single unit against your unit cap, meaning that you can add an entire army of redcoats with just a single available space.
And old-timers should be happy about the return of Wonders. This blast from the past makes its first appearance in AoE III, with their construction now being a prerequisite for age advancement. Basing historical ages on building the likes of the Great Buddha or the Confucian Academy seems artificial in addition to the usual resource demands, although you can't argue with the flavor they add. Each of the 15 Wonders (five per civ) grants powerhouse abilities like boosted attack damage and hit points (the Indian Tower of Victory) or the ability to instantly heal all units (the Chinese Temple of Heaven). These historical and mythological elements add character and tactical considerations to the choice of what Wonder to build and when.
About the only thing that this expansion doesn't get entirely right is multiplayer. The new Regicide and King of the Hill games are been-there, done-that, and new maps like Honshu and Silk Road are merely variations on old themes (even if the latter's focus on controlling trade depots is sort of nifty). Still, you can't complain too much because the new civs and gameplay features mix up the old multiplayer maps so much that it's like playing online for the first time.