I think if you can handle Mario Kart you can handle this game. The one disappointing thing though is that things like your lightsaber aren't going to be controlled with with IR. You still have to control them with the joystick. The review I read said that they wanted to make the controls solid, even if that meant they didn't push the boundaries of the Wii. Kind of smart I think, I'd rather have solid controls, than some janky experimental stuff.
And still, Zelda is using the blue tooth to communicate sword action, not the IR receiver. For something like this game, you can pick up people and objects and move them around, this is where the IR receiver would come into play the most. Being able to point where you want to set the object down, or even throw the object.
When Zelda uses the IR, it's to aim your bow, or sling shot...something like that. All the game has to render is a simple target, and the target never has to change size or anything like that. When you start to pickup an object, now your having to render the object in the 3-D space and depending on how fast the object is being moved around, your GPU is working over time with collision detection, and image resizing requests, and any number of other calculations that the Wii may not be able to handle at once, AND process the IR input.
I worked a little bit with IR devices in a design class I had not to long ago, and processing the input from IR, at least with the equipment we had, was very intensive.
So I'm sure that the Wii could do it, but I think the point was that they wanted to focus their resources into other areas of the game, to round out the overall experience.