I noticed that the “Hard or Hardest” AI’s focus is on training more villagers than military units. That is why they don’t feel as aggressive as “Easy or intermediate” Ai’s.
Easy and Intermediate Ai’s would train more units than villagers over time and would feel more aggressive but they upgrade technology much much slower or even age up.
On the other hand, Hard and Hardest AI would train too many villagers almost 80% (are villagers), and train very few units to fight, and feels so easy for most of the players. But they would upgrade technologies much much faster and have a better economy than Easy or Intermediate AI.
Please balance the number of villagers and military units trained by the Hard or Hardest AI so they would feel more difficult than the Easiest or Intermediate AI.