Wait wait wait Pu33ed. Remember that I'm not playing samurai wars - give me link, maybe I will back there :)

Anyway I agree almost with everything you are talking about, maybe without one thing;

When the units are unbalanced the strategic AI doesn't know which units are unbalanced, but after a while the human player figures out which units work better and will buy more of them giving the human an advantage in the battles

Here I can't agree. Into Barbarian Invasion Eastern Rome (into single player, when commanded by AI), used great army, which influenced multiplayer a lot.
They were taking 20 units of plumbatriarii - and it was almost undefeated.