Any chance of this being someone from the near future? Superman said he felt temporal energy in the teleporter fields, right?
The fact that everyone in the room aside from Damian is shown to respect Superman makes me think the idea is to do a future Damian who has grown to respect him after years. That way it is Damian, but it isn't.
It would sort of "rhyme" with Jon's future related stuff. Damian underscoring how young he is, and Kate bringing up her kid made me think along these lines.