Expert.

Pause... yes... make a coffee come back, answer the phone, do the dishes... but I hit the alt-T combo far more often.

It is so easy to make a balanced army to take out the opposition that it needs the morale bonuses to even have a chance to stay long enough that I might, might I say get the chance to get the butcher vice. Typically have at least one guy I am training up to be an expert attacker... so he is always facing 2:1 odds and winning.

Now to spice up the game and make it difficult I find my 'See no Evil' rules a real nasty way to play the game.

No borderforts or their equivalent. No strategic pieces outside of my lands. I am blind to the composition of my enemies stacks. I have to design the most effective balanced force I can. To up the difficulty again I play on Huge unit sizes. Since I have no forts rebellions happen more often and they hurt a lot more, maving huge units of rebels is painful. This and play Poland at the same time and you have to spend some time thinking.