Re: Star Wars Episode VII
I don't necessarily mind the Luke idea, but I think it may be premature, someone reading into something and running in the wrong direction with it.
As for what happened in ROTJ, I don't believe he turned there. He was angry, furious even, and he definitely lashed out at Vader... but he never used the Force during that fight. He overwhelmed Vader physically, but that's it. Without touching the Force during that time, I don't think the "taint" of the Dark Side would affect him.
Also, I've got my own theory as to the "balance of the Force" concept, and it strongly affects what could potentially happen to Luke. I think Lucas cheapened it significantly by dumbing it down to "balance = kill all the bad guys". It wasn't Vader's destruction of the Emperor, or his own death, that balanced the Force. It was the moment he turned back. Never before in the history of ever had anyone turned back from the Dark Side... "once you start down the dark path, forever will it dominate your destiny, consume you it will". You never heard of a Sith being warned against kittens and unicorns because they could turn him to the Light and dominate his destiny. It was impossible. That, in my opinion, was the imbalance... you could fall, but only one way. Anakin was created by the Force itself (he had no father) for this very purpose. He fell to the Dark Side because he had to. It makes his fall that much more tragic because he really didn't have a choice. He fell because the Force deemed that it was necessary for him to fall. It gave him the power, the immense power that no Force user had ever wielded before, to facilitate his turn back. That moment when he turns to the Emperor is when he ripped himself away from the Dark Side, breaking the imbalance and allowing, from that point forward, anyone to switch back if given the motivation to do so. The EU (non-canon, I know) shows people switching sides like they change their socks.. Oh, I'm having a bad day, fall to the Dark Side, but I'll be fine by the end of the book. It was Anakin's sacrifice that made that possible.. he was the first.
That also means that any change by Luke in that direction is not in any way permanent. Yoda's statement was invalidated after what Anakin did, and the Dark Side does not necessarily have to "dominate" one's destiny if you don't want it to.
