.....course a UAV needs a pilot or some kind of handling team on the ground. ATC would prefer to speak to a human I'm sure.
ATC "Unmannedxxx turn left 345 decent to 3,000"
UAV "unmannedxxx bad command or filename"
Seriously though it's not a case of uploading a flight plan and away you go, any flight between A and B involves the pilots interpreting and acting upon 1,000 of variables some can be handled automatically others need a human.