My thoughts on Rose Quartz
I personally really like how Steven Universe presented the Pink Diamond -> Rose Quartz story, mainly because it actually puts us in the shoes of the main characters. At least with most of the other shows (not anime lol) that I watch, we the audience are more like sentient beings who know more or less where the show's themes and struggles go towards. But with SU, we're literally experiencing all these events happen in real time along WITH Steven, and in turn, experiencing his emotions as they come along. So obviously, we begin to first be confused yet facisnated with Rose Quartz, which morphs into irritation and downright frusteration with Pink Diamond.
Of course, there are literally thousands of analyses that defend this arc and I'm not going to just repeat what people 5-10 years ago have already said. However, I will say this. Pink Diamond clearly matured, learned through hard work, and quite literally changed to be more empathetic and care for others. It's clear that her time as a Diamond made her spoiled and entitled, but as she learned more about Earth, she learned more about not just humans, but how to really feel for others as more than just something to lay with.
She even works on herself AFTER she's mostly known as Rose Quartz! (I have no idea if the following scene takes place before or after her faked shattering ;-;) When she sings "What can I do For You" with Greg, she STILL HAS that mindest that HUMANS are TOYS! I'm really emphasizing this point because we KNEW that the Crystal Gems have been here since the beginning of the first human civilizations at the very least, and STILL Rose has yet to move past her ignorance of other species. This proves that she is NOT a villain, and NOT an antagonist (since that's not what SU is about).
TLDR: Despite the way Rose Quartz's story is presented to us, if you take the time to really see her growth, you'll know that she's not a antagonist, but a flawed person working on herself, just like every single character in Steven Universe.
