I think you degrade your mission flexibility if you remove the easily reprogrammed human control unit from all of your aircraft. These bio-units occasionally make mistakes, but they are more easily re-tasked for changing tactics, they can use their imagination in an unexpected tactical situation, and so on. They can't be hacked and they can still operate when their controlling information system (aka radio data link) is being jammed.
Pilot-less civil aircraft would have one mission - to make the number of take-offs equal the number of landings and make the rest of the journey as smooth as possible for the paying luggage. For a strike aircraft it's not so simple...