3. Competition
This story is able to compete with Marvel's plan in Phase 2; to take the brand to a cosmic setting. This goes back to Darkseid being the villain, which addresses a cosmic threat that requires more than just the Man of Steel, and opens the door to interdimensional travel as well. If they pull this off this becomes DC/WB's standalone ensemble movie event. Allowing our heroes some time off to return to their individual cities; at which point the focus can be turned towards solo and/or partner films.