These 3D whizmos, like for example LEAP motion (incredibly cool), all work great.... for about 20 minutes. Then you put them in the drawer because they require too much muscle coordination and energy to operate. in contrast when you REST your finger on a scroll wheel or REST your hand on a mouse it is not merely not moving, it is at rest in 3 dimensions. it only takes a small effort to move it, but you are not having to run a whole lot of muscles in coordination to keep the hand or finger in a constant position. it's hard to poise your hand in empty space. In the old days, good typists could do this with hands poised over the KB and fingers hovering above the keys. Most people now days use palm rests or put pressure on the keys. those old time secretarial pool typists had to sit up straight and brace their feet on the floor to pull that off. Girdles probably helped!
the first successful mouse replacement will have that feature. Perhaps something with haptic feedback to support your finger a little till you really want to move it.
personally I suspect the some sort of eye motion or maybe a joystick like thing will be the first 3D controller that people can use for long periods.