Stock question, stock response:
To me, MVAM as depicted makes a great deal of sense. That is, it is very sensible to use uncrewed starships in combat, and it is also very sensible to make those uncrewed starships as large as possible (there's no logic in using tiny little combat drones if those don't each individually possess the threshold strength of hurting a starship, and we have seen how poorly small craft in general fare against starships). However, as "The Ultimate Computer" shows, giving control of large combat starships completely over to an intelligent computer is unacceptable in the Trek universe. Hence, it makes sense to remotely control the large combat drones from a nearby spacecraft that safely stands out of the fight.
Furthermore, it makes sense to cluster the drones and the command center into one single starship for deployment runs. That eliminates the need for big warp engines in the command section, and in turn allows the command crew direct access into the drones for maintenance and repair. Housing the drones aboard a big-engined carrier vessel would be wasteful because the drones themselves already have the big engines as a combat requirement; the classic main functions of the carrier, such as C3I, maintenance and ammo replenishment, can be provided by the tagalong command section.
Two drones per command section is a good start, I guess. This combination isn't too much bigger or smaller than the average crewed starship, so it can use the same spacedocks etc. Also, the size of the Prometheus command section is sufficient for turning the cluster of two drones and one crewed section into a "crewable" starship that can perform noncombat missions as needed, even if combat missions only call for a very small operating crew.
(The depiction of MVAM in "Message in a Bottle" suffers from two basic faults IMHO. First, we saw the command section taking part in battle. But that was an exceptional situation with inexpert Romulans in command of the swarm. Two, we saw and heard that only four people are needed for operating the ship, and indeed Starfleet has only trained four - this is very little for the maintenance tasks, and hardly warrants a sickbay several decks down when an EMH console on the four-man bridge should suffice! But the statement about four trained people might apply after the Romulans killed all the crew of the ship, potentially a much higher number.)
Timo Saloniemi