...

You know I absolutely loved Nirvana Initiative and I think it fucked massively, but if I could change anything about it I would add maybe 5% of Aiba & Bibi talking about how isolated they exist from everyone else.

AINI is, fundamentally, a story about bitches who are only half people and will make it everyone else's problem; Jin & Uru are self-explanatory, Ryuki is fucked up in large part because of his brother's death, ect ect.

It would reinforce this theme nicely to have Aiba and Bibi both have more issues with other people. Aiba, because AITSF repeatedly emphasized that she and Date were basically extensions of each other (and you could argue that in AINI she runs into a couple mistunderstandings with the Mizukis assuming they'd act like Date does.) For Bibi, well, "it's true that we can't get ourselves boyfriends, because we're human weapons and we can't contend;" aka she is superhuman, which really means not a human, she has abilities no one else has and trauma no one else would understand, the only person who could ever come close to understanding her is her sister. I also think it'd be a nice hint for the timeline; only one Mizuki feels fundamentally alien to other people, only one Aiba is profoundly missing Date.

"What about regular Mizuki, isn't she half a person too?" no see Bibi based her entire sense of self on "I need to protect my sister no matter what." Meanwhile Mizuki, the "perfected" version of Bibi, is a whole person on her own.