On the Prometheus/Defiant comparison, note that it would take three ships 4-times larger than a Defiant, or three ships larger than a Constitution, to match up to the volume of a Prometheus. I have no problem with such a "small" being suitable for "deep space" operations.
If we're accepting the whole notion of "surprising" the enemy with MVAM, it all means somehow preventing the enemy from identifying the class of ship by some technowizardry. In which case one may simply be able to disguise a squadron of ships as one big ship or whatever you want.
So what are you going to do? Build every ship with MVAM? That's a waste. If you only built a few with MVAM, that's useless because the probability that there will be an MVAM ship exactly where you need it is low.
Smaller ships need smaller crews. Is it acceptable to need slightly more personnel to man three smaller ships than to man one larger ship?
And if you're deploying a MVAM warship to an area to wait for trouble, then there's nothing wrong with deploying smaller warships in squadrons which are rarely intended to split up. That way you don't need multiple Captains and can get away with lower ranking officers "commanding" the other ships.
If we're accepting the whole notion of "surprising" the enemy with MVAM, it all means somehow preventing the enemy from identifying the class of ship by some technowizardry. In which case one may simply be able to disguise a squadron of ships as one big ship or whatever you want.
Two problems with that.
1) you assume that starfleet is "sending" them on a mission instead of just encountering an issue or being "the closest ship". By that theory, starfleet would operate like the klingons or romulans and send 2 or 3 ships everywhere, all the time.
So what are you going to do? Build every ship with MVAM? That's a waste. If you only built a few with MVAM, that's useless because the probability that there will be an MVAM ship exactly where you need it is low.
2) Sending 3 ships would require 3 crews, 3 captains, 3 first officers, etc.
Smaller ships need smaller crews. Is it acceptable to need slightly more personnel to man three smaller ships than to man one larger ship?
And if you're deploying a MVAM warship to an area to wait for trouble, then there's nothing wrong with deploying smaller warships in squadrons which are rarely intended to split up. That way you don't need multiple Captains and can get away with lower ranking officers "commanding" the other ships.