"When we started this project (Legend of Zelda) many, many years ago with the original NES, it was from the beginning about the sword fighting. Starting actually from the 'Ocarina of Time,' the developers were more eager to make more sophisticated movements of the sword competition." - Shigeru Miyamoto
Motion controls allow for better sophistication of moves, but Miyamoto also stated that this can make it tough when looking for the perfect balance.

"When we look at today's fighting games and many other games, sometimes we have to feel it's rather difficult for us to realize the perfect balance between what you are actually doing with your hand against what you can see and realize or reproduce on your TV set. In other words, I really want people to feel, 'OK, I'm doing better and better by practicing, for example, my sword fighting.'"

Link