But then you have to see that Luke's attachments to his friends caused him to rush off to face Vader, and ended costing him his hand. But then on the other hand, had he not faced Vader, I don't think Vader would have been redeemed in the end of ROTJ. Luke confronting him had a huge impact on Vader's psyche and reminded him of the things he gave up. Heroes often walk a path as narrow as a razor's edge. But I think faith and love are the things that allows Vader to come back. My head is starthing to hurt now.