I can't imagine what a replacement would look or behave like. You can replace your keyboard with almost anything that proxies human to computer, but nothing else is the same or as capable.

The radar video is impressive (as were Leap Motion videos, which didn't live up to the hype), and sure it makes sense for extending a watch or phone, but the problem with autocorrect and voice recognition and predictive keyboards and spell checkers is much of the time, I'm not writing clear, coherent, English sentences.

Sufficient advances to write foreign words and jargon and deliberate misspellings and usernames and hostnames and slang and quotes which are deliberately not spelled normally?

A lot of the claims about "you'll just think it" hide the reality - e.g. when I try to speak a password and I can't, because it's just a pattern of motion (and you can't escape this overall problem by saying you won't need passwords in the future).

Human hands are dextrous and sensitive, almost no other body parts are anything like as much - voice is laborious and prone to problems of pronunciation and tiredness and background noise and homonyms, anything else isn't going to come close until you can have brain surgery implants - and even then a) no thanks and b) I bet that still underestimates the complexity of reading clear intent.