It doesn't change a thing. While that "level 1" explanation is certainly a possibility, it also fails to explain why all the other Jedi couldn't learn it as well. Obviously Qui-Gon was the only one who "had what it took" to discover this technique. Whether he did it in life or in death doesn't change a thing about the rest of the Jedi : They weren't able to find out about it until Qui-Gon came back to teach them. Another weird thing with that theory : if Qui-Gon learned this technique during his life, why would he keep it to himself and not share it at that time? That's pretty selfish for a "selfless" individual. It's pretty obvious to me that Qui-Gon only discovered the technique in death. Therefore, he was already in full possession of his skills and conscience, while dead.