I think it's seriously underpowered.
The picture of the captain/pilot of the ship below the health and power bars always shows a unit, even when there's only one crewmember left. Of course, it COULD simply be a lack of bitmaps there, but to fill in the hole in logic, I'll go with underpowered.
Still, there's another question I'd like to know... are there absolute equal amounts of Zoqs, Fots and Piks on their homeplanet? Is there a government system that restricts breeding and matches everyone up into a unit? I don't think this is answered in any of the games.
Edit: If they upped the crew to 12 it probably would still show a unit when there's just one crew member left, making it even more underpowered.