More to this, when Luke destroys the dark side he could say something like: “at last you are free, father.” (SuperShadow: Awesome.) This would explain a bit of how the dark side works and would explain why Vader "must obey his master" and how Vader says to Luke that he: "don't know the power or the dark side." (SuperShadow: Excellent points.) Think on it, it might grow on you, it́s sure a thing a lot of people can relate to. (SuperShadow: Your idea will be forwarded to Lucas.)
I'm pretty sure that a black hole sucking up all the dark jedi in episode 9 (according to our good friend SuperShadow) wouldn't destroy the dark side. This dude really needs to stop smoking weed.
And Superraptor you answered your question. He gets his ideas from bull's crap.