The player can only view and manipulate one part of the map at a time in an RTS. This means that the more micro you require for a player’s units to behave effectively, the less can happen on the battlefield at once. This tends to reduce mental APM in favor of increasing physical APM. Better interfaces can reduce the physical APM necessary to sustain good micro, but an interface innovation can’t change the fact that it’s only physically possible to focus on one limited area of the battlefield at once.
Micromanagement requirements are a cheap way for RTSes to build more “skill” into their gameplay. If the sufficient amount of micro to make all the units on the field effective cannot be achieved ever, the game will seem to scale with skill gain indefinitely. As the player improves his micro and learns to multitask better, she’ll play better. This can continue for a long time in a game with a significant micro requirement like Men of War.
Micromanagement requirements can be measured in the average opportunity cost of having your view centered over a certain unit at a certain time as you effectively micromanage that unit. If you lose the game because one squad of infantry stands still while being slaughtered by easily avoided machine gun fire, the opportunity cost of microing your tank well at that moment is enormous. The more often this kind of disastrous misallocation of micro can occur, the more micromanagement-intensive the game is.
Micromanagement can be minimized systematically in two ways: changing the scope of the game and implementing AI that does micro-level tasks better than the player. These tend to be implemented in the same game most often, as can be seen in RUSE. In RUSE, tanks will kite infantry automatically, infantry will ambush nearby vehicles, hideable units will hide and unhide as necessary in forests, planes will circle and engage targets on their own, vehicle crews automatically repair their vehicles when out of combat, infantry gets in trucks for long journeys and gets out at the end without player intervention. The scope of the game allows this to make sense—the game plays out on a large scale, that of Supreme Commander. The AI fills in where micro would otherwise be required; it allows the player to focus on strategy instead of the player needing to focus on individual unit tactics because he fears his units will get killed through their own stupidity.
Some games, like Men of War and Company of Heroes, can’t avoid micro because their scope is so small. WIthout micro, these games would lose much of their appeal. An AI strong enough to allow the player to focus on higher-level concerns would tend to intervene in areas where the player would expect to have to take action, leading to an annoying struggle between player and machine over fine-grained orders.
Micromanagement should be minimized as much as is reasonable, though, because coming up with a great strategy should be more important than putting your limited viewing window over the right part of the battlefield at the right time. If a game requires twitch skill in issuing orders rapidly, the purpose of the game—strategic problem solving—can all too easily be subverted.