My thought on PF's is that they need a new ship trait that reflects the fact that these ships have very limited combat duration and don't have any (much?) of their hull space taken up with crew quarters, supply storage, etc. Consequently these should have more available systems space for a given hull size than a fully autonomous ship. This would require that they be accompanied by a tender which would have the opposite trait - having less available system space than normal since the tender also carries crew space and stores for the PF's.
Brian
Why not just adjust the Tech Levels appropriately to achieve the desired result? Whether doing away with crew quarters and supply storage or utilizing advanced technology, the end result is fitting more stuff in a given hull size. At the tactical level, the difference is really just fluff.
Adam