There's merit to that. Sort of like the Roman triarii tactic - send out the trash as a first wave to soften up the enemy line. If the trash breaks through, well and good; if not, you've softened them up for the real attack. The same principle applies here, but only if the conversion from antiquated fighter to UCAV is cheap enough relative to new, modern systems not to impose much of an opportunity cost. An attack by converted legacy fighters (especially equipped with more advanced future AI with high levels of autonomy) must still be addressed and will sap enemy defensive resources, especially if the drones are carrying modern munitions and can lean on networking with more advanced systems to make up for their own shortcomings.
