Another thought: Not sure I agree with the statement that the bigger army almost always won and there were no random influences. Hattin, anyone? Outbreaks of "plague" at most sieges? The rallying of the Christian defenders at Antioch, after finding the holy lance and seeing St Michael lead the heavenly host against the Saracens? Sure, faulty strategical decisions, the lack of hygiene, and starvation/exhaustion would be more accurate parameters than random events. Still, the combat interface should be kept fairly simple, so some random events might be worth considering, to add flair.
He was referring to the way combat worked in CK 1...were the size of the army was close to 90% of what mattered. Then again, I hope it wont be like in Rome were the generals stats made up 90 % of the army's combat power