I would say it'd be a bit better if you were either A: Starting off with the cargo or B: Racing through the level to get the cargo, then having to race back.
Imagine having to flit your way all the way through Oblivion Approach to get to a drill/refinery, then having to dash all the way back. Cut through walls, use some access tunnels, dart through the enemy before they even know what's going on. That would favor a single ship, as a large group wouldn't benefit, as it is only one piece of cargo. Aside from running intereferance, a larger group would simply get in the way of a single ship running through it.
Meanwhile, it would be a challenge for the captain. Having to avoid certain enemies, deciding whether or not to cut through a wall, etc.