matril

It seems very odd to me that anyone would latch onto that change as some kind of error or plot hole. I thought it was quite deliberate from this exchange that Vader has begun to shift from a certainty of the Dark Side's greatness to a deep regret but feeling of depressing inevitability. Just one of those examples of how we all have our personal interpretations, and the meaning of stories is whatever we make for ourselves. (Though of course my interpretation is the most correct. ;)