my main complaint with this game..(which is otherwise awesome) is that there is no "this civ does this better than that civ does"
The only real differences between the civs are economical.. meaning some will get gold faster, others will get wood faster..etc..etc..etc.. From a military perspective..all of them are fairly similar. Using the mongols does not make you a ranged cavalry civ.. their ranged cavalry isnt that much better than the normal ranged cavalry.. so if you charge with alot of golden horde..your just gonna get owned.
SO.. the game is great..adds alot of new stuff to the genre while keeping true to what works and what is fun.. but the civs need more drastic bonuses/weaknesses to differentiate between them.
As for build orders.. this game doesnt really do build orders. The nature of the resource gathering, and the sheer amount of upgrades means that you will do different things in different orders depending on how the game is going.