How do you think precious Rey will react when she finds out that her saber was used to slaughter jedi kids?
Better question: can we really expect DLF to confront her with this slightly problematic detail, given that their attitude is to take what is good from the legends?
But giving them 8 months of benefit of doubt that they have stumbled upon this angst gold mine...
I generally hope that TROS will take a closer look at the Skyfam, good and bad parts alike. Basing on the movies alone, I'm not sure how well known the Anakin-Vader identity is and more importantly if Rey knows about it (and from additional materials I can only conclude DLF footsoldiers aren't sure either). If that indeed is an issue then I think the fact that the Excallibur turning out to not only strike at the ones force holds in its wrath would definitely come forth, hopefully even placing the well deserved shadow on the kybers' moral sentience lore.
Additionally, I still hope Rey will build her own lightsaber from a new kyber like a grown up she's supposed to become and the legacy saber will be allowed the place of honour as a symbol of both the light and the dark sides of legacies.
That being said... I can't see this info alone being a drop to overfil some chalice. Given that Rey's means of coping with problematic news is to either force fit them into the puzzle or go to the gym and forget about them, I can't imagine her for example refusing to use it when pragmatism calls.
So, essentially I can either see it as an element of a longer Skyfam morality clean up scene or, unfortunately, having little plot consequence, if it's brought up at all.
