[UsagiTenpura]

Oddly enough its RGD that cleared my mind about a lot of things concerning Umineko and Higurashi, I believe I understand most things of it now, and that Rose Guns Days probably explains more clearly the "needed" mindset to reach the solution then either Naku Koro Ni stories.
Well here's an example I guess. The murders on Rokkenjima, all of them, goes back to a single thing : By her own hands, Yasu destroyed her relation with them. We're not talking about murders. Even the fact that she's responsible for destroying the relations can be seen as subjective, but these are the conditions. They "leave the game board" and "it's Beatrice's fault", anything beyond that is entirely beyond the point. This is why even our confession didn't get into details about the why dunnit or exact M.O beind used in a certain "death room". It's something that she didn't have a clear idea about at first, but always knew, from the moment she tried to solve the Epitaph, that it wouldn't end anywhere good, and in the two years of span from that point on she began to imagine all the paths it could lead to, and was stuck in her own puzzle, the labyrinth of her own thoughts, and fears. She knows her time is "short", represented by the bomb, and how she learned to enjoyed living while it's ticking (such as her entire relationship with George).
A lot about her can be more easily understood if you try to think of a 19 years old who was so lonely she had to befriend a 6 years old in order not to feel eternally alone. Yes everything she did to George was seriously wrong, but from her pov it's something like this or never having anything. Kanon, the development of her intelligence, always knew she was wrong, but Shannon, the development of her emotions, couldn't help herself. She does feel wrong for what she did, so wrong that she can't tell us openly, and anyway even if we get it, we're going to judge and hate her for it.
All the wrongs she did to George are nothing to her next to having solved the epitaph tho. She is entirely unable to think in term of her own personal greed ($$) as far as that goes. What Yasu "has" is not money, it's a place on Rokkenjima - not the "island" but the community - losing that is destroying her own world. That's what she inevitably sealed while solving the epitaph and intuitively knew before even starting to reason it out. She's however so absorbed in that mindset that she eventually loses the ability to see clear, simple solutions, such as talking it out with Battler.
Even tho everyone on the island did wrongs, often to her own self, she understands them rather then judge them, and desperately hoping someone could do the same thing for her. One one side she can't forgive her own self, and on the other side she does understand her own situation, so she's stuck, at the "peak of purgatory", unable to judge her own self. Waiting for someone who actually properly understands her to really judge her properly - even tho she knows it probably won't happen, because the possibility exists, it's torturing her, and she can't discard it. It's the same as how she reasoned out everything about Battler. It's shown to us as like her own escape from reality, but it's more like she can't help thinking about all the possibilities and is unable to really give up because however how small it is, there remains some where she'd be "wrong to give up". Bern and LD's relation kinda shows it. They constantly talk about boredom, of course, what else does Yasu really has to think about in her life? To her own despair, no amount of certainty will lose to the witch of miracles inside of her. She's unable to create her own "gold", to believe, by herself, in her own conclusion. She needs someone else, and she's going to submissively adopt the view of that person, like she does with Maria or George for instance. However she can't submissively adopt the view of someone when she has certainty that they are wrong. In the end she needs someone who'll be able to understand both her tricks, and the "heart" that lead to them, and then can judge her, to make her "rest in peace", at which point she'll accept whatever verdict.
So in the end she can't forgive herself, something she probably learned from the way Natsuhi treats her mistakes, and doesn't believe people can really understand her either. She doesn't trust others, because both to her and each other, she's seen weaknesses as something others will use to attack you (think of all the stuff about the adults between themselves) or to show how better they are then you (like Gohda with her, or even her original introduction to Maria).