Maybe I am getting hold of the wrong end of the stick, but...
How is it an improvement in usability if, whilst transferring a large file between two devices, both those devices become unusable during the transfer? If one person has to stand and hold their iThing in the air, whilst the other is laid on the desk... how can either be used for anything else?
Can't think of the last time I used a PC and it was unusable for other tasks whilst the file transfer chugged away in the background.
This would be as useful as a phone that can't do anything during an install from the Appstore/Market/Wherever.
As for flicking... how would that cope with a file flicked across an office with 5 devices all set to recieve and all within a naroww field? Would it be as accurate as attempting to throw a frisby to your kid, only for it to land on the shed, in the pond or over the fence?
Also, how would the two devices know where they are in relation to each other? I'm no genius on such matters, but, I've not heard of any technology that can scan a room and identify the exact location of other phones. Perhaps someone can elnighten me on that one? Surely you'd need to use triangulation to pinpoint the location (GPS isn't accurate enough and doesn't work indoors reliably) ? If so, doesn't the proximity of the sensors affect their accuracy? On a phone there's only so much distance you can put between sensors, unless this comes with a couple of attennae you strap to your hands and wave in the air?
So, assuming the location cannot be accurately identified, the "flick" is no more than dragging your finger off the screen in any direction and the phone pairing with another and transferring it. May as well just have a context menu pop up on dragging a file, offering the choice to bluetooth, email or sms it!