But to answer your question, the idea is that Rey needs to embrace her inner Dark Side in order for the dagger to work, and she only learns that after getting the instructions that 3PO translates from the dagger. If she just immediately decides “Imma use the Dark Side here,” there goes her inner conflict.
Okay, I can understand that. But what I’m trying to argue is that it shouldn’t show her anything at all until 3PO reveals that information to her. There’s no way to convey any sort of difference in handling it in the film.
So up until she is on Endor, the dagger will only be whispering to her because it was the murder weapon of her parents. Since she has the same blood as them, she can sense that.
I still think a 3PO dub is viable, but I’m wary of any other changes. That’s what I’m trying to say I think.