I always thought the MVAM (multi vehicle assault mode) was pretty much a useless idea. When a ship breaks into a 'war machine' and 'lifeboat' that makes sense as they have two distinct functions. But breaking a ship into multiple pieces for combat just doesn't make sense. You have to crew it with multiple capable command crews to work each component when the ship is in MVAM mode. Then you have to give it multiple components (warp drive, impulse engines, phaser banks and torpedo launchers) to allow each separate entity to survive independently in the event one or more is destroyed.
Just build multiple starships.