Re: punching video, fast very fast
A long time ago there was a chinese martial artist who used to win many competitions with just one technique. Basically he would cut down the striking arm, and his other arm would come over the top to strike the jaw with a vertical punch (known to kung-fu students and similar to the strike proceeding irimi-nage shown in 'Budo'). He only needed one punch, and he'd practiced it enough that he could kill someone with it.
All these amzingly fast punches and combinations of striking techniques look nice when people are scoring points. However in reality you just want one thing that is devestating and delivered with perfect timing. I'm not saying these martial artists aren't great - but that martial arts isn't like the movies where you spar for hours on end. The ideal is to finish something quickly and definitively, and it is all in the distance and timing, not in the number or combination of techniques.
Why don't we practise against combos much in aikido? Because we don't stand in front of someone whilst they deliver a combo. When someone strikes you hard/effectively they are striking with their centre. You can strike very quickly in one direction because you can continue your centre to rotate or direct around this one point. If the recipient in this video had moved at the initiation of this fast combination, would the person have been able to make any use of this combination? In fact, should the person have ever got so close to the person without striking or kicking the attacker in the first place? Aikido is one of the few martial arts where we do very little pracitice in which we assume uke to just stand there and soak it up, or to move in a predictable way.
Now I'm not saying aikido is a top fighting art in anyway, but it is an extremely useful self-defence art which has many many beneficial aspects to its training method which are not realised in other martial arts.