I began a game with France.
I decided to declare war to England immediately. Portugal joined them later, and after Austria. I thought I would be raped but I managed to kill surprisingly lots of isolated packs, they didn't do a big pack, and Burgundy also declared war against them later so they let me alone. I took all the provinces of England on the continent except Calais.
I waited a bit, declared war against Provence which was allied to England. Piece of cake, I took Anjou and Maine.
I was thinking to increase my money and one-two years passed, when suddenly I became the king of Provence thanks to my grace and beauty :S. Someone knows about it ? First time I see it. It gave me Barrois, Provence and Draguignan. Without fighting or doing anything. Pretty nice.
So everything is going well. I still have doubt about this war system being better or not. I have the feeling it advantages a lot the human player. I am in 1458, and I have already a big part of France. We will see.