Something predicted at the beginning of the Wii generation seems true: that an inevitable downside of motion controls is that what's good for one person will be bad for another.
Ironically, we got so few Wii games with proper motion controls - like Red Steel 2 - that this problem never really got highlighted. Most Wii games, even good ones, just use the gesture interface as either an IR pointer which is pretty hard for any player to fuck up using, or as a "shake" device. Just shake the Wiimote however you like to make something happen.
But take the plunge into serious, hardcore gameplay like with RS2 or this game, and you run into a mostly unexplored world of issues.
Example: I hardly ever, so far, had the stab motion go wrong on me. Someone else playing here was having a lot of trouble. He kept getting diagonal slashes when he tried to stab. So he watched me play a bit.
He tried mimicking me, and it worked a lot better for him. I watched him play, before that. To me, it looked as if whenever he tried to stab forward, without actually realizing what he was doing he was twisting his wrist to the side and actually swinging the wiimote in an arc. He triggered a diagonal slash.
And that's the issue. Ever seen someone who when they use a game pad, every time they mash a button with their thumb, they unconsciously twist their whole hand around or such? Motion controls highlight stuff like unrecognized body language and spasms, twitches, or habits that we don't ever think about. With video games, usually only the games that require the most rigorous and complex execution, like playing a fighting game on a joystick, highlight that yes, playing games is hard. It can be an actual discipline to use an input device precisely, at high speed, under pressure. Most games are, in fact, not really designed to push the player that far.