If space-time expanded I would think the planets would just slide and stay in their original positions, seeing that space is without friction. In order for your idea to work, distance itself would have to expand between systems. And I don't think that is possible without some ambient dark energy. Even an either would still be without friction. In other words it would take a tremendous amount of energy to push against the systems within the universe. Where's the energy in your idea without dark energy?
I think that 006 is saying that the universe is expanding due to the gravitational constant which is the same as saying dark energy did it. I think also that the difference in terminology is that the cosmological constant gets away from trying to understand what dark energy is or what drives the expansion. You just plug a variable constant in to the math and of you go.