Yeah, my thoughts exactly. When I saw it, I instantly thought of Man Hacks from Half Life 2 - flying drones with buzz-saws attached. They were far less maneuverable than these quadcopters. Buzz-saws are for chumps, though - I'm sure these things could carry more than sufficient C4 to ensure that any human-sized target was eliminated completely in the sort of way that their relatives hope their dental records are up to date.
With a Gyrojet style weapon, it would be easy to fit 4 or 5 rounds of ammo with the stopping power of a 45 caliber on such a platform. Taser rounds could also be quite doable, and even adapted to the same launcher. This would be complimentary, as Gyrojets have a minimum range of 15' or so, which is a practical max range for a Taser.
Terrifying.