This, in combination with random chance through dice rolls. To me, Warhammer has done a decent (not 'good') job at balancing the effects that dice rolling can determine games. Some of my most memorable moments playing (both casually and competitively) include one unlikely dice roll on a spell, combat round, leadership roll, etc. that determined the outcome of the game (in both wins a losses). If you make things too mechanical and predictable, it loses that fun factor that makes you want to participate in each game turn/phase (this is especially true at the competitive scene). If you make things too random, the general feels like their tactics didn't determine the outcome and they'll lose interest. I've been at both ends of that spectrum while playing Warhammer, at both casual and competitive locations; give me most of the former, with a good mix-in of the latter and you got a balance in my opinion.