I'll throw in as another person wanting to add modular command centers. I think there are a number of possibilities there, and it simplifies matters if you want to change the purpose of a command-center (just change the module rather than destroying the center and waiting for the cooldown to expire). It also makes the purpose more flexible --- you want the command station to be able to defend itself a bit but need to shut down teleporters (the main time I use log stations, which can be annoying when a mixed counter-attack wave is inbound), or you want heavy defense but are willing to trade a bit of firepower away to offset the cost difference between econ and mil, etc.
(And I know that the Home Command Center is the "King," and the King is one of the weakest chess pieces, but seriously --- if I'm in charge of the last remaining command post in the galaxy after a "IT'S SUPER EFFECTIVE!" genocide of the human race, that sucker is gonna have as many guns as it can fit.)
Of course, balancing it would be a pain, and it would make a core part of the game more complex, but those are small prices for more modular happy happy fun times right?