I feel the use of cheap (well, comparatively)drones will change how we think. Imagine a well protected fox hole and a $200 drone delivers a grenade inside of the foxhole clearing the foxhole. A $2000 drone firing a hell-fire missile. These drones have the ability to get into places conventional forces would have a costly time taking. I think of the damage 100 drones would have in a small area. It may turn out that self propelled artillery and drone observers may be a game changer in future conflicts. Electric drones make almost no noise compared to combustion powered drones so they could work well at night. Drones with laser designators. Drones, because pilots are not endangered, can be operated more boldly than manned aircraft. I see that the only practical defense would be the heavy use of ECM and jamming across the entire battlefield. I believe that the drone has the potential to greatly reduce armor's effect on the battlefield.