9. Steppenwolf's Motivation
One of the biggest complaints that Justice League received was its bland antagonist, Steppenwolf. In the film, he intends to merge The Mother Boxes to terraform Earth into a base for his master, Darkseid. Considering how much the villain is built up, it seems disappointing that his ambition boils down to the unoriginal trope of "taking over the world".
But Snyder intended Steppenwolf to have a much more fleshed out backstory. The reason why he is covets The Mother Boxes is because they contain the essence of his mother, Heggra, (who was his sister in the comics). After unifying The Mother Boxes, Steppenwolf would released his mother's spirit and be blessed with godlike power. Tired of living in his leader's shadow as a henchman, Steppenwolf intended to use his newfound abilities to overthrow Darkseid and become the ruler of Apokolips and Earth.
Steppenwolf's original motive was canned but there is one clue hinting at his scrapped backstory. In the trailer, Steppenwolf says, "No protectors here. No Lanterns. No Kryptonians. This world will fall, like all the others." This line was meant to conclude with Steppenwolf saying, "You will be free, mother."