I can See how XS and S cores come in handy as intruder vehicles so you Just Arm them with enough to crack Open a door and have the Guys do their worst otherwise crippling ships is tricky in Terms of balancing as this could get Out of Hand in large Engagements real quick
Take EvE as a reference Here where new Players get custom F2P doctrines that specialize in ewar and do massive damage to hostile fleets by Just supporting the Main fleet.
Still i feel a Battleship on a L core should be a Statement on the Battlefield and Push Back the smaller cores ( XS & S ) unless they have a significant Numbers Advantage ( Like 50 : 1 )