It's pretty amazing that we can program a computer to win at chess or go, but not to use its units effectively in a TW battle. EB battles are too easy because the AI still does the same stupid . Probably the #1 issue is the misuse of cavalry and generals. The AI loves to use its cavalry in melee combat with spearmen.
You can nerf the player's units all you want, or buff the AI's units, the same issue will always be there: bad tactical algorithms.