This has been discussed before and rejected by Frontier.
Since I have zero interest in adding another weapon system to my ship (which is basically all fighters are), I currently have no use for ship launched fighters. But I'd love to have a small 'freight hauler' slot for my Anaconda. Fit it with a ship that has super cruise only (no hyperspace jump) and room for say 64 units of cargo: this would make it possible for me to use my Anaconda for trade at small stations my big- ship can't land at. It would also be handy for planetary landings: leave the big ship in orbit, take the freight hauler down to the surface fitted with an SRV bay.
But apparently this isn't in the cards, as much sense as it might make. I'm not sure why, although I'm sure someone will shout 'unbalanced!' very loudly now.