I noticed one thing when I played with an allied AI vs two normal AI enemies. When the enemy is about to reach my town, 5 seconds early my ally teleports to my base... well in that case it was someting good, but I think it's a remarkable advantage against the enemy. I think it should happen in the human way, sending units when the town is under attack.
Other thing that would make the AI more "human" should be removing the advantage to know where is the enemy town. I think the AI must send an assault group to the unexplored mines, if it can't find enemies, go to the next mine, and so on until it can get an enemy town.