Mohs receiving these trope categories. Broken Pedestal, Ain't to Proud to Beg, and Death by Irony (possibly).
Anise having an older brother that developed a deep hatred towards their parents, Mohs, and the score. I'm not sure if it was ever mentioned that she's an only child.
Shortly before the original reveal is supposed to take place, Arietta and/or Largo reveals to the rest of the party that Anise has been leaking information to Mohs. Which leads to Anise being tied up, or locked in a room to prevent Ion's death from happening.
If Largo was there for Mohs' death/defeat, he mention his mother-in-law, and call her worthless for betraying him and Sylvia. Worthless as Mohs is.
If Tear was there, Mohs would beg her, asking if she wouldn't leave her superior to die. Her response, "Superior, no. But you, AN EXCEPTION".
After Tear sends vague visions to another version of herself, the reboot would cut to a grass plains. With post-haircut Luke and the party getting captured by a suited stranger. Most of them were arguing with each other. And they begin telling the stranger what they've been through that led to this point. So it'll be one of those "how we got here" moments.
Herzog explaining his reasons for massacring Guy's family. I actually don't remember if he did in the original game.
Guy, Jade and Natalia getting called out for withholding vital pieces of information.
Ingobert losing the respect of his people for ordering the execution of Luke and Natalia.
The ghost of Yulia appearing as a wandering spirit. Seeing how the people have become over-reliant on the score. And that she's to blame for the deaths and disasters it caused.
Continuing from this. http://kh13.com/forum/topic/97157-possibilities-for-a-tales-of-the-abyss-reboot/
If you have any ideas, feel free to reply.