I don't really have anything in mind for Zechs' arc or anything, if that's what you're worried about! One scenario could've been Zechs coming to terms with what had happened in a healthy way, realizing how much he'd been manipulated, coming to terms perhaps forgiving himself for everything that happened -

- But realistically, Zechs is a Mess. That was very, very unlikely to happen, not anytime soon, especially with his terrible coping mechanisms of ignoring his problems and pretending he's invulnerable. So Treize returning alive and back with his charismatic shenanigans will only add to that. I'm completely on board. :D