Earlier quoted context omitted.
It will also have to drastically downplay the importance of footwork. In a real swordfight, where to put your feet is nearly as important as where to put the sword.
This is also true for a plethora of sports games as well, specifically racquet based games. Swinging the racquet is less than half the battle -- footwork, in most physical types of activities, is much more important. Omnidirectional treadmill? http://en.wikipedia.org/wiki/Omnidirectional_treadmill
About 3:50 into the video entitled "The weeds" Mr. Stepehnson says "We're going to start with an off-the-shelf controller that anyone can buy today. This eliminates the risk that we'll blow this by failing on some ambitious custom hardware project. From there we'll iterate based partly on your feedback. "
So no treadmills at first.