Shu has crazy arbalesters. Their upgrades are full and cheaper, and additional have 2 more damage. It’s too powerful in Arena Fast Imp. There should be a nerf, like removing the Thumb Ring, or having the Bolt Magazine cause their reload time longer to offset the effect of Thumb Ring.
The War Chariot is both useless and inaccurate. Just remove it.
Wu is relatively fine but the food bonus is too aggressive in a short term. A skilled player can utilize it in a very strong way. I’d like to change it into: Buildings/ships provide 20%/10% food of the wood cost when built. That could be more modest and more helpful in a long run.
The Jian and Fire Archer are full of nonsense gimmicks, especially the flaming arrows with a range of 13. There should be reworks for them.
Wei has to be buffed, clearly. With an average economy, only focusing on cavalry make it pretty one-dimensional. The Plate Mail and Barding Armor should be given to it without a doubt. The lack of effective ranged fires is also an obvious problem.
The Tiger Cavalry is embarrassed as there is also a strong Heavy Hei Guang. Their roles are pretty overlapped. Personally I’d like to rework the Tiger Cavalry to be the unique upgrade to the Heavy Hei Guang, and like to introduce a new UU at the castle. Besides, remove the Xianbei Raider, who is supposed to be the UU of the Xianbei/Hu own civ, bring back the Heavy Cavalry Archers.
Heroes are too expensive to use, easy to be killed, and out of the AoE2 style. There should be some replacements…
More details of my opinion on the 3K: Move on and make Three Kingdoms more accurate and balanced