Hi, I have some observations:

1) It is impossible to assaul enemy fort, even if defended by only 30 foes and you have 10x advantage. You have to siege it for months.
2) War is extremely unprofitable. Due of long campaings because 1), I had ridicuously big unkeep of my troops. Siezed sites had just little of loot. No money income from looted cattle.
3) War is a must. I had toto go wars because public opinion in counties go low if I was in peace too long + proper development is possible only through stealing cattle from your neighbors. Also your neighbors are quite aggressive.

All three points result in this: All development of my sites was extremly hard. Building of anything is still very expensive, but mostly I wasn´t able to accumulate enough money for it. For example: I had like 130 gold, but I had to go fight for cattle because my ppl started to be unhappy because of long pease. After long war I had like 110 gold, but meanwhile one by one I was attacked by 3 different rulers. After years of boring, unprofitable conflict (but without any lost battle) I ended without any money and with negative balance.