The Wii remote is a repackaged Sega Activator.

[Elusive]

The Activator training video

IGN re. Mortal Kombat on the Wii

Midway has kept the gestures easy so that anybody can pick them up - accessibility was a primary goal for the developer, which ultimately wants even novice players to pull off fatalities. So, to throw a fireball, you might merely hold B-trigger, and make a motion from the right to the left and back again. Or, a swiping motion up and then down again. Or an underhanded half-circle. Or an over-handed half-circle. And it's really not much more complicated than that.

Good idea in theory, not so in practise - kind of amusing how history repeats itself, no?

[j_factor]

Sounds quite a bit easier than the Activator. The Activator was like, break the low beam on panels 4 and 6 to do a directed jump-kick.

[Rusty Venture]

It's just a really fancy Powerglove actually.

Except without the glove, lack of software, and extreme lameness.