I think VR/AR/MR have the most new realestate in terms of power-UI because you are physically present within the interface. The best examples to me are VR & Art based [1] which let you create 3D objects in a 3D space or Paint like you would in front of an easle. The UI's range from grabbing a spraycan suspended in mid air to menue controls for spline points and camera views. Still evolving and no where near feature parity with established tools but I see this changing over time.

[1] My Shortlist: OpenBrush, Gravity Sketch, ShapesXR, Vermillion, Vartiste, & Brushwork.