Superman should easily trounce Steppenwolf, so that part was accurate. The problem is, so should Wonder Woman. I don't believe Steppenwolf has ever been considered a major hitter in the Fourth World saga. He was only present in the backstory issues in Kirby's original run. A plot based around him leading an invasion with some Parademons is unimpressive for a JL story, so somebody or everybody is gonna get nerfed.
A beefed up Steppenwolf should still be solod by Wonder Woman, while Superman fights someone like Kalibak and Aquaman deals with the Deep Six, etc. A full scale invasion from Apokolips justifies League involvement. Steppenwolf by himself with some Parademons is something Superman can deal with in an afternoon,.