I understand what the lines are trying to convey, I just don’t think they succeed. There’s too much focus on Leia’s failures for it to feel like a positive/reassuring pep talk. The main takeaways most would get from those lines are that Leia gave up on being a Jedi due to fear and that she lost everything and everyone that she cared about, which is just very bleak. I mean, compare it to what Han tells Ben: “your mother’s gone, but what she stood for, what she fought for, that’s not gone”. I think this scene needs a similar, positive spin, which again is what the original lines did by making it Rey’s destiny to finish Leia’s Jedi path.
Then there’s the issue of the idea that Leia would renounce the Jedi out of fear of “the hatred that consumed her father”, that just feels out of character for me. There’s no reason to believe Leia would go down a dark path after dedicating her whole life to the fight against opression. Furthermore, in TFA she says she wanted Ben to train with Luke specifically because “there was too much Vader in him”. Now, why would she send her son to train with Luke because there was darkness in him, when she stopped training with Luke out of fear of the darkness in her? This is completely contradictory, she would’ve forbid Ben from training in the Force if she believed that could fuel one’s darkness.
But she didn’t, because that’s exactly what Jedi training is supposed to be about, learning to control your emotions, rejecting the easy & seductive path. Obviously in the case of Ben it backfired, but he was too far gone (and even then Leia didn’t lose hope in him). Leia never shows any such signs of darkness, and if anything it’d make MORE sense for her to seek Jedi training to quell any potential darkness, just like she did with her son.
Rejecting the Jedi seems like a major sin for the story this movie (and this whole trilogy) is trying to tell, I mean there was an entire movie about how bad it was for Luke to reject the Jedi, and he only did so after everything went down in flames. For Leia to give up over some vague fear of inner darkness makes her look weak and foolish. She would need some major motivation (like a premonition of her son’s death) for her to throw the towel immediately.
And no, Leia was never a Jedi, she gave up on it along with her saber on the last night of her training, so she never became a Jedi (here you’re even replacing that line so we don’t know how far along she was in training with Luke). She was not a Jedi in TFA or TLJ, Luke was the last Jedi, then Rey took over after him. In this film we see Leia taking on a mentor role for Rey, and it’s explained she can do this because she trained with Luke when she was young, but that does not make her a “Jedi Master”. She doesn’t “teach” Rey anything, she just takes her to the place where she trained with Luke 30 years ago, and tries to give her encouragement along the way, while Rey runs training courses and studies the ancient Jedi texts. Rey is the sole heir/last hope of the Jedi, Palpatine tells Kylo killing Rey will “end the Jedi.” Leia is never part of that conversation, because she’s not and never was a Jedi.