We could replace Kylo’s “Do you still count the days since your parents left? Such pain in you. Such anger.” Since we are already replacing the following dialog anyways!
Hal, how did you feel about the lightspeed ramming stuff?
EDIT: I think a funny response for him on this context would follow the same pattern as Rey’s “I see through the cracks in your mask. You can’t stop seeing what you did to your father.” Maybe he could say in response, “I see the cracked crystal in your saber. You believe that you will never be a true Jedi.” Then it would go to our other new lines: “My mother doesn’t see the darkness in you. Your friends don’t either. But I do.”
I like this idea a lot. I would, however, be careful of removing Kylo’s mention of Rey’s parents leaving her and that it’s still a big deal for her given the reveal of her parentage later.
As cool as it is, I think the crackling saber doesn’t require a verbal explanation given that it was visually set up in the previous movie well enough.