My biggest question is does this mean that we might get mental images of other people? It could be interesting. Regina talking to Cora, maybe Emma talking to Neal. I think this pretty much opens up all kinds of interesting conversations that might help the rest of the cast heal.
The way they’ve set this up, they could totally expand on it like that. I wonder if the others would need it as badly as Rumple does, though? Even if they’re not exactly getting along, they do still have each other in that group, as opposed to Rumple being completely alone. I think Tink will probably fill that “ghost from the past” role where Regina’s concerned. Maybe Hook would hallucinate Bae, and Emma would hallucinate Neal? That could actually set up his legit entry into NL, if either/or Hook and Emma have “seen” him previously, so they don’t initially believe that he’s the real deal when he really does arrive.