Personally, I think QR code video is a great solution.  But that's significantly more challenging than simple QR codes.  And so far, Armory doesn't have a utility for scanning even regular QR codes.  It will have to be a robust solution, because there might be megabytes of data to transfer (could be fixed if we had something like SIGHASH_WITHINPUTVALUE). 

Also, I was hesitant to implement something that requires the user to have multiple webcams, and have their webcam drivers setup, and then try to figure out what to point where and when, and have wires everywhere.  It's doable, but it's also not necessarily user-friendly.

That doesn't mean we shouldnt' do it, it's just that it's not a perfect solution for a general purpose tool.  I'd rather people use USB, than get fed up with something complicated they can't get working and forego offline wallets entirely.

However, we have more resources on our team now... we may be able to prioritize it.  Right now we have an audio cable solution in the works, which also utilizes an analog channel which should be pretty darned secure.  But it's not ready yet.