This an argument one could make, yes, but not only does War help to account for his subjects' proficiency in combat, the Emperor was most well-known for being a godlike warrior, and it was in combat that he was most successful. Many of his creations had a flaw of some sort that ultimately proved fatal to their original concept. (see: most of the space marine legions) However, when the Emperor was fighting on the battlefield, nothing went wrong enough to prove a loss for him.
It's undeniable he has craft, and hard to argue that he doesn't have occult given his knowledge of chaos and psychic power.