The real problem with swordplay on a Wiimote is the fact that a sword is a solid object.
A 1:1 mapped sword motion would be cool, but a real sword has weight, as well as air resistance working against it.
As well, what if you hit a solid object with your sword?
Your Wiimote won't stop and/or bounce off the object, so while the sword would stop/bounce back, your arm would keep going. How would this map to ingame movement? Would you have to restore sync by moving your arm back? What if you don't do it fast enough? Will the game detect it as a *further* return movement, causing you to turn?
etc.
It'll really only work with lightsabers, which lucasarts IIRC already said they're interested in making a lightsaber style game.