The barbarian AI was very strong in Imperial-Age because:
1. It will temporarily adjust the proportion of farmers according to their arms in order to achieve the best economic balance.
2. It will build enough buildings, such as stables, barracks, castles.
3. According to the situation of military strength, it can adopt three attack modes: DUC patrol attack + TSA+Attack-now.
4. It can cooperate with attacks when it encounters allied offensive teams, such as cavalry with archers.
5. It will give priority to forward Castle, using the castle as the attack base.
I hope the above information will help you to improve AI.TRiBaL_Warriors is too conservative and cautious in his offensive strategy, giving the enemy enough respite to wipe out the enemy at once.I'm chinese，so sorry,my english is poor.