Tobar said:

You're leaving the preceding line out of the equation: "It seems in your anger you killed her." Following that up with, "It no longer has any meaning for me." Doesn't make sense or sound right. Going back to your original point, the word "it" is still a very personal word. "It" is directly addressing the situation, "that" is an impersonal brushing off of the subect.

lol see i just take it the entirely different way...the slight "offness" of it isn't wrong to me, it's just off because there's no conversational acknowledgement there. you're trying to tell this machine something and "he" responds like a computer. not that vader's a computer, but its nice to convey that level of rote response in his debut moment. "it" is as rote as it gets.

at least to me

not trying to force my opinion, just feel unusually invested in this tiny sentence lol