I think they made Rey a Palpatine for a few reasons.
- To give fanboys a reason why Rey was so powerful.
I think sticking to a “chosen one” approach would have been enough. I never liked this angle though (it was a weird trend during the 90s: Matrix, Harry Potter, Star Wars, …), but between a random slave being “chosen” by the Force and someone who inherits her powers from genetics (but not her parents ?), one option still sounds better to me.
in the final movie we got, one can argue we kinda merge both approaches though: Rey is chosen by the Force AND she’s the granddaughter of a powerful Sith (something which could be applied to Anakin if one overreads Palpatine dialogues though during the Opera sequence in Ep3), but still doesn’t really explain everything she knows, everything seems so easy to her, it’s really boring for me to follow her adventures in the ST (I stick to my point made roughlty 6 yars ago: Finn should have been the main protagonist of the ST, not just a comic relief) 😕 She’s like the Avatar the last airbender, but without the same empathy and without the fun…