War involves decision making under conditions of extreme stress, so there is an element of unpredictability about outcomes, but excessive randomness can just make it silly. If your gaming time is limited, systems which involve extremes of luck can produce very unsatisfactory outcomes, which is why my regular group hates Piquet, BKC etc. If you have more time, these things average out.
I like cards. Some players claim cards are just random, but as any poker player knows, it is all skill and calculation of odds. Clausewitz also thought a game of cards was as close to a model of command as you are going to get, which is good enough for me.
"Mistakes in the initial deployment cannot be rectified" - Helmuth von Moltke