Maybe after the Crisis is finished, CW will release a mini episode where Harbinger explains the new timeline.
Theyve been saying the Legends of Tomorrow premiere episode which acts as the final chapter of Crisis as being "a very special episode". Perhaps the new revised history of the Arrowverse ?
When it comes to comics,one person's "fan-service" is another persons personal cannon. So by definition it's ALL fan service. Aren't we ALL fans?
SUPERMAN is the greatest fictional character ever created.