James Sterrett is a professional wargamer — his title is Deputy Chief, Simulations Division, Digital Leader Development Center, at the Command & General Staff College, Fort Leavenworth — and he discusses three things gamers usually do not have to deal with:
First, we usually have far better knowledge of the situation than is possible for real armies; consider that one of the key pieces of information from ULTRA decrypts was the Axis order of battle in various theaters – simply knowing what units the Axis had was a major intelligence coup, but such information is routinely handed to players. Moreover, the scenario usually tells us what the friendly and enemy win conditions are, while those are often less clear in real life.
Second, in nearly every game, our forces do exactly what we tell them to do, exactly when we tell them to do it. In the real world, subordinate forces need time to conduct their own planning so they can carry out our orders, and they may not go about the task exactly as we envisioned. (The best game I’ve played for experiencing these challenges is Panther’s Command Ops series with the Command Delay set to the maximum value. I’ve also heard good things about Scourge of War in this regard but have not personally played it.)
Third, gamers are usually planning by themselves, which means they have to explain everything only to themselves and to the game. Military staffs deal with more information than one person can process; even a battalion staff is likely to be several dozen people. Getting this many people to pass information among themselves efficiently, and let alone coming up with a coherent plan that everybody understands, requires practice.