Turns out, Cyborg, the half-human half-machine member of the team, has been confirmed as one of the Mother Boxes in Justice League.
The big guy won’t be in Justice League (as far as we know), but the villain Steppenwolf (who has been confirmed for the movie) is searching for the Mother Boxes on Darkseid’s behalf.
BvS introduced the Mother Boxes, devices that act like super-supercomputers in possession of fantastic powers and abilities.
And this means that Cyborg is crucial to the plot of Justice League, which will be neat, since we haven’t seen much of him yet aside from that one short scene.