AOK was a really great game my only problem with it was that it ignored the Slavic civs, and it didn't have nough civ specific units.
WHat would have been good was a revised AOK/TC with all the same civs but more unique units.
Of course the western EUropean civs would share a lot of the same stuff but you wouldn't have to deal with Chinese Knights or celtic horse archers, come on some of the stuff was ridiculous.
Here are the CIvs which should've been added:
1. Mali
2. Russia
3. Poland
4. Vietnam
5. Cambodia
Of course they add in civs like the Huns which really belong in AOE, and civs like Spain which basically didn't exist until the very late part of the middle ages. Not saying htye shouldn't be there its just well the X-PAc should've included more civs.
Oh yeah one more thing, we siege towers.
Unit changes:
Only Koreans, Mongols, Turks, Byzantines, Sarecans, and other civs which actually used cav archers get them.
Also only Franks, Britons, Celts, Teutons, Goths, and spanish get knights.
Mongols and Chinese get heavy cavalry, but not knights.