Seems like in 4e, actual wounds are only used for cinematic purposes. Most "wounds" are really just minor hindrances. I read an article not to long ago that was creating lasing wounds in 4e using the template for disease. It was pretty cool really.
And DM fiat seems to be the only real answer fr inflicting serious wounds. 4e never really introduced anything for called shots, etc. Though in a recent issue of Dragon magazine they did talk about wounds in Unearthed Arcana.
In terms of martial characters being able to induce wounds... That makes perfect sense. Their training could've helped teach them where to hit an enemy to only wound, or incapacitate him or her. But I also can see magic users being able to curse others. Perhaps giving them a permanent penalty of some sort.