Is Rose Quartz a Good Person?

Or gem, I should say.
Either way, the short answer is no. Not at all.
Sure, she was abused, mistreated, and neglected, all of which most likely messed up her psyche and moral conscious. But that doesn't change the fact that she hurt thousands, affected billions, kept up a silly rouse for several millenia before her true identity got out.
Which, honestly, was a bit of a slap to the face to the fandom considering how much we used to adore her.
In reality, however, she was an immature, insatiable, dismissive, easily unimpressed sociopath looking for her next high. I say sociopath due to her lack of concern for how her actions affected others and how her "highs" always seemed to be some major change in the way things were. Everything she did was always done to an unnecessary extreme that ended up hurting someone. Even the creation of Steven himself was an all-or-nothing solution to her want to create life.
From the beginning, she's characteristically portrayed as nothing less than a brat. A child who has no idea how the world works and wants to explore. However, said child's parental figures already know they'll get bored with the real world just like that. Right there is a near perfect description of Rose. A child in search of entertainment who doesn't know her actions have consequences. I will give her this: the Diamonds' treatment of her was more likely than not the source of her apathy.
Still, she whines and cries until she gets what she wants. A colony. Once finally gifted with one, she not only cruelly abandons her long time friend, Spinel, but she also quickly starts to abandon her duties as a leader. Honestly, Pink Diamond only ever shifted in the first place out of pure boredom. Not because she was already thinking of freeing her gems--she never really thought about that. She wanted Earth. Gems who struggled in Homeworld just happened to be her best bet at an army, made clear to her by Garnet. Suddenly, she's not just looking to free Earth, but also attempting to free reject gems. In retrospect, this does end well, giving the Crystal Gems a chance to emerge and build a free world. But for thousands of years before anything truly like that is achieved, Rose Quartz gathers a plethora of gems, only for them to be shattered, bubbled, or corrupted to defend their liar of a leader. Think of all the gems who happily gave themselves up for Rose Quartz and her cause--now think of how many will never know the truth.
Who knows what she's done? Hell, Bismuth was just poofed, bubbled, and stored away inside Lion without second thought. Hidden in a place Rose knew no other gem could access and didn't even bother to alert her closest confidant. Instead, she placed Bismuth in a spot supposedly impossible for anyone else to enter, then lied to everyone else about her whereabouts. For a hot moment, she had us fooled. "Shattering is wrong." We all sympathized for a moment. But locking up your friend with no sure means of escape without second thought? She might as well have.
So then, what good has she brought? Well, she was the foot in the door. As twisted as her motives were, she started the war that banded the Crystal Gems together. She inspired so many gems to be their best selves and power through until they knew their own strength. She created Steven, who ended up being more suited for the role she took on.
Nearly nothing she did, in the moment, was necessarily right, but the Crystal Gems were always able to push through and make good of it.