Okay here i am playing around with custom battles in STW

I give myself 20000 koku
enemy hs 5000 koku random army setup
late period
(ie: they have this pretty mincy army)

i take 16 units Heavy Cav, 3 and 4 honour with 2 weapon no armour

I lose. Their general runs away, they kill my general.
I lose 2:1 heads.

I tried my best to surround them

btw, i reckon the graphics engine in STW is soooo much better than MTW - the camera swings around sooo much easier. And the atmosphere is heaps better (esp the fog).
And i think the AI is a little cannier - i see it really taking hill tops, having vanguards etc. Probably b/c asian battles were all much faster than slow poke western ones anyway.