I'm rather baffled by how I would use speech to paint into a Photoshop window. Force feedback motion already exists for 2D painting -- graphics tablets are standard equipment for artists.

You wouldn't "paint into a Photoshop window". I'd imagine saying e.g. "put a circular animation of growing fern around the center of the pulsating ball" and then tweaking via force feedback some of the parameters of the fern or its growing.