I've seen some people float around the idea of Terezi reviving John by prototyping a sprite with him, but the first thing that came to my mind was the ectobiological equipment in Dirk's lab. I think she might end up using it to create a perfect copy of John, although that could result in a Vrissy type of situation where the new John is biologically identical despite being a completely different person in almost every regard. Maybe she'll forgo trying to revive him altogether, or try to abstain yet finally give in? I'd love to hear what you folks are thinking.