Hey what do you think of Leaf? I think she's the worst and a shit sister, she acted like Lazuli she was in the wrong for hating their dad! Who does that? The fact she peaked in Chapter 1 shows how much she sucks.
Leaf is an...interesting case.
I think I can understand what the intention was with her character. She's meant to be the gentle, nice character that is supportive, kind, and doesn't hold grudges. But, due to the surrounding factors, her character ended up backfiring, and EV-Zero unintentionally made her look nearly dismissive and certainly negligent over what's happening around her.
So, when it came to the topic of their father. Leaf doesn't hate him while Lazuli does, and Leaf is insistent on giving him another chance, maybe to explain things. I think this debate between the two sisters could've been expanded more, and there could've been some sort of neutral ground. Of course, Lazuli does not have to forgive the same way Leaf is not obligated to not forgive.
But she provides pretty shallow support and advice.
One of the biggest cases is Speed and Lazuli.
When Lazuli reasonably questions if Speed would ever like her back because of her common behavior of beating him up, Leaf simply says, "Don't worry about it..." (I believe in Chapter 3)
Even when I read that years ago, I was pretty confused because Lazuli had a generally reasonable conclusion regarding what Speed would be feeling toward her. Yet, to Leaf, Lazuli should just not consider that, and Speed will totally, realistically not only forgive her but also love her back.
Not to mention, the actual Speed abuse that she bears witness to on several occasions. She pretty much does the bare minimum and partially calls it out on Lazuli that, no, she did not have to beat the crap out of him and/or give Speed a bloody nose for whatever reason Lazuli has(which is not much of an actual good reason unless being called a "nasty girl" like once or twice in Chapter 1 is reason enough to punch someone in the face...). Other than that, Leaf basically shrugs it off as "Lazuli being Lazuli," which is apparently shared with everyone else in the squad.
However, there is potential. If anything, it could've been used as a reasonable flaw for her character. Leaf could've been a character where she's gentle and kind yet doesn't lift a finger to physically stop anything or be direct. She holds back and allows conflicts to escalate. To add to this, due to having only her sister to rely on for the majority of her life, when it comes to Lazuli, Leaf struggles to actually call her out or say that her sister is wrong in something. She, at most, would say that Lazuli took it too far, but other than that, Leaf holds back, and that allows Lazuli to escalate conflicts repeatedly.
It'd be a pretty good visualization and, unfortunately, a realistic phenomenon where just because a person isn't the one hurting someone directly, they're not fully absolved of guilt because that person allowed their friend/sibling/etc to hurt that person(especially over and over again) and they weren't making an effort to put a stop to it.
It's kind of like having an older sibling that you trust and have a good relationship with start to bully another kid. Now, you're in this dilemma of pushing through your personal perception of your sibling and calling them out or letting it continue.
Via this flaw, Leaf would go through conflict with Flare(who hopefully wouldn't like what Leaf's sister does to his older brother), Speed (the general victim), and Lazuli (the trusted sister that Leaf relies on).
But that's just me and how I think Leaf's character would've worked.