As sad as I am that it’s not here at launch, I’m excited for one specific possibility.
The possibility of the people joining using their multi-player Spartans. I’m not a developer by any means but I also want to believe it wouldn’t be THAT challenging to implement. Lore wise it could also make sense, you were a surviving spartan, along with some of the surviving marines. A lot of the marine diologue saying “spartan” instead of chief, or referring to 117 specifically, makes me extremely excited for this possibility.