The first thing that happens every battle is the enemy cavalry vanguard running head first into an arrow storm and dying.

I don't see that happens in my game. The only cavalry that charge head first are archer calvary to haras your line (which is quite annoying). But their infantry and melee cavalry always advance in formation together with their generals, that is if they're the one attacking. If they're defending they just hold position waiting for me to get to them.
The only groups that charge at me disorderly are bandits.



This does not happen in every Battle, this happens for battles where the enemy side has skirmish cavalry. AI does not suicide melee cavalry if It does not have skirmish cav.
For example, Sturgia is a faction which usually suicide its cavalry units in almost every battle.
Bandits are tards ? shouldn't be.
What annoys me is my cav charging enemy infantry when I want them to attack enemy to their front - cav. .. ignore the spearmen.