That's indeed what we're trying to test to the extreme - to see how far we could go with just vision. We haven't done heavy excavation workflows yet, but we have some early success with some excavation workflows with just vision input and joystick action output (even without joint angle feedback!). We're betting on having really huge data with compact observation input and experiment to see if it holds water. If not we can always dial it down and add more sensors/feedback.