I've been thinking about it and it seems pretty clear: The Wiimote works for sports and shooting because those use basic actions that require skill. You can swing a golf club wrong and have the ball go off into a bunker, you can aim incorrectly and miss the target. But what do most brawlers (any kind of melee combat in a game) ask you to do? They've usually got a predetermined set of actions and the difficulty comes from picking the right action at the right time, it's a digital selector where there are only a limited number of discrete results.
There's no difficulty in swinging Kratos's swords on chains no matter how difficult the weapon is probably to wield, you just select a slash and Kratos does it for you with perfect accuracy, he never swings it wrong and has the blade harmlessly fall to the ground, he never accidentally hits with the wrong part and loses his grip on the weapon. There are no errors in the act of using the weapon. When actions can never fail a button is the logical input, similar to the up and down of a button there are only two states for the action: active and inactive. The IR pointer doesn't help much with autoaim shooting either but manual aim has been standard for a while.
The logical conclusion would be that a brawler game should require the player to execute the actions skillfully instead of merely requiring the player to pick an action. For example a WMP-based sword game could track whether you're really angling the blade along the slash, if you hold it wrong the damage is reduced or you might even lose your grip on the weapon. The swing would have to be properly straight and go through, if you try nonsense like changing direction in the middle of the swing you similarily mess up.
Of course the actions would have to be toned down to something humanly possible, many game characters have inhuman stamina levels and I'm pretty sure no real soldier swung his sword about once per second for several hours. That's where the straining waggle comes from, expecting the player to keep up with a superhuman routine. No sports game expects you to keep swinging a baseball bat this rapidly for this long. Of course with buttons we never really had the means to develop combat systems that require skillful actions, sports had to use massive workarounds and only did that because they had their concepts pre-written already. Videogame combat was designed to ignore the difficulty of executing the action outside of maybe some button combo to trigger it.
Many who hear of 1:1 sword controls immediately imagine themselves as movie stars or jedi knights but this is an illusion created by games that did all the hard work for you. Removing this automation would result in duller-looking combat since it's no longer hollywoodized but it would overall be more intense for the player himself.