The biggest showstopper for me on this is the hugely disappointing top speed (40 km/h). I'm an alpine skier (ex-racer) and the only times I go that slow is on transport stages. This thing literally wouldn't be able to keep up with Usain Bolt running the 100m. It needs at least twice the top speed.
That's actually pretty speedy for a quad, especially to remain stable. If you want to race at 100MPH and have gyro-stabilized video you should get a helicopter and a camera crew.
I for one would prefer the aerial robot following me to not be traveling at 60MPH. That's asking for a serious injury.
Well, I would imagine a lot of your speed is downward right? Then it's a matter of a controlled decent really. I'd guess that would increase the top speed of the device as it's really just falling out of the sky and steering.
Well electric motors can accelerate rapidly, but if they're pulling something heavy, all you'll get is rapidly spinning electric motors and a slowly rising object.