Hey,
The core rule book, page 201 Drone Rigging : "Most of the time, drone rigging is done by remote commands, which rely on the Pilot rating of the drone to carry out. Commanding a drone is a Major Action"
Also "Control Device" matrix action is Major action. I would assume that Command Drone is really a major action, because "jumping in" cold or hot sim gives you extra initiative dice, which can be swapped from Minor to Major.
Thus Rigger in hot sim could have enormous amount of "Command Drone" actions, which on one hand does make sense with high RCC ratings and Swarm Armies, on the other, thanks to RCC, you can issue the same command to all the drones. Such as "Attack the target".
Maybe, in order to issue multiple commands to different "fleet" of drones, you have to use minor action in conjunction of a major action, just like Multiple attacks.