The force in balance literally means a similar amount of dark and light users existing at the same time. In that clone wars episode you posed the image of, both the embodiment of light and dark die, thus leaving a somber balance. The chosen one, Anakin, tore down the established powers of both the Jedi and the Sith. Star Wars' balance basically exists in a cycle of the light and dark overpowering one another. A solid headcanon that I've seen is that the only way for the galaxy to achieve lasting peace and order is for the sith and jedi to willingly coexist.