While balance is a game design term and not something typically associated with simulation, it is still a simulation game and to a certain extent balance still matters. Unless the rules of the simulation world are nearly identical to that of the real world we must apply balance and game design to overcome these limitations. One of the unfair advantages that AI posses is the ability to see and shoot through trees. Mission designers may realize this capability and place sams outside of wooded areas, however with CA players can order AI sams to move within a forest, thus negating the intent of balance from the mission builder. Yet the "foul" location of the SAM is but one alternative. CA players can move the sam anywhere, which creates a lovely situation where an attacking player controlled aircraft simply won't memorize the location of specific threats on subsequent replays of the mission.
I am curious though- if the slots aren't occupied by people do those assets still exist in the game as ai until someone comes in? Or are they completely separate entities with start points similar to what we are used to?
Unless they added a feature that limits which groups can be controlled, any unit that exists on the map, which has the capability of being directly controlled (FPS), can be AI or player controlled at any point in the mission. Some units are limited to an RTS type of control, but you can change the groups ROE, State, formation, and waypoints.