The interesting thing about 10,000 hrs is that what you spend that 10,000 on is what you end up mastering. And while repetition might seem the fastest way to racking up the hours repetion or 'blocked learning' is useful only to a point, beyond that it actually inhibits learning by giving false confidence and learning can go backward. Fortunately in the traditional arts there are all the ingredients to avoid this through variety, stress testing, as well as blocked learning drills.
One of my favourites teachers, David Brown said most of the time in the dojo is wasted which he then wen on to say with bowing in, exercises you don't need, talking, wasting time with an uke that doesn't get it , wasting time with a teacher that doesn't get it, paining up etc... adn when you cut class time back the parts where you are learning can be pretty small.
Next I want to say to Daniel, that the whole idea that the time spent talking in a dojo is wasted, is the biggest load of baloney i have ever heard. The whole idea that training with a uke who (doesn't get it) or a sensei who doesn't neither, what exactly is it supposed to be that they are supposed to be getting? Your style of martial art? Well maybe not. But the aiki-do is the way of the real ninja, and it takes determination, commitment and engagement. Things which cannot be learned over night, and take many months and years even to get down to a tee. Anyone who somehow believes that the ritual bowing in and out, or even colloquial discussions in and around classes, can be skipped over for some 'better' style, needs to have their head examined if you ask me!