I would try and make a military expendible version that used rigid-type explosives as the structural members. I would steal that Israeli method of putting very small titanium particles in the explosives. The titanium particles fly out at terrific velocities but quickly scrub speed after a very well defined spherical area. This gives a very good and well defined danger zone. One could fly one of these things into a room and attack one individual and the rest could just be 'flash-banged'. It would be useful to fly into buildings through doors and windows and even attack weapons like RPG rounds. The 'kamikazi-robot' would set them off with a direct hit. They could use LED type night vision and fly into caves, etc.
Counter-measures would spring up. Thin netting would catch them. Shotguns with bird-shot would be enough to take them down.
I was amazed at the toy my kid got. Its a very light RC helicopter and it appears to just run from a super-capacitor. Daddy like.