If you stand on something that moves, for example, and jump straight up you still move in the same direction as before instead of suddenly standing still in the air and falling off (I hate games that with mechanics like this).
Yes even in the code examples we have here, there is no though of a added vector for inherited movement vec of the surface.
Ed- Is anyone currently thinking of doing a footsteps-like bone driven animation system.
System that allow active modification of the animation do so by adjusting the base hard coded bone animation with factors such as the ground height and slope.
I'd hate to try to start a add-on if someone with much great skill is already on it.