I personally guess that she is just underdeveloped, that's all, for being the core character to all the A plot's in the three films. I don't really hate her, she is just kinda there though, unlike Finn or even Rose, unlike Anakin. Hear me out though.

This might get me a lot of hate, but until a really down time in my life I rewarched Revenge of the Sith, I didn't really care about Luke, since I came for the Prequels. It was only after that I really got to kinda sympathize with him truly, after realizing how much he took from a father who would have loved to but never could spend time with him due to his own failures. Its a family drama and both of the previous trilogies were growing of age stories, really. In fact, under Lucas, this was going to be repeated again, but surely in a different manner. Disney, contrary to what many people say, did try to incorporate at least some of those aspects earlier on when Michael Arndt was present in production for TFA in but it seems to have gotten sidelined in favor of JJ Abram's plot right now, which develops on her in the first half, but personally the execution of the latter half of the film really failed for me in terms of delivering a gut punch, considering how little time she spend with Solo and how he wasn't her true dad.

With Rey's lost parentage, unfortunately, that family drama aspect is gone and now it got blown to bits because being related to Palpatine is more shallow story wise than even being related to some drunk, due to Rey's want to be a Jedi which Palpatine simply laughs off and moves on from.

I mean just look at what they are doing in Andor, with both Cassian and Syril Karn having some intense family interactions between them that reveal a lot of their own personal motivations or despairs. I wished the same kind of exposition for Rey, whether Han or Leia would have been her parents or not, or whatever other details were there. Too little on her parents thanks to wanting to keep the mystery of her parentage more mysterious than it needed to be.