This is the best they could do for the first Justice League movie. Ignoring the fact that Steppenwolf is a stupid idea for first villain, they had to make him this weird ass demon
Who cares? He's only there to be the leader for the faceless goons that the heroes punch. It's the exact same strategy they used in Avengers.
It's a BAD idea to waste an interesting and good villain on the first movie, because the first movie is all about establishing the relationships between the characters and showing off cool scenes of the heroes beating up mooks. Just look at New 52 Justice League where Darkseid had to be reduced to a Big Guy for everyone to punch because they couldn't waste pages establishing his pathos and motivation.
As for the design, it was either this or make him just a guy in a helmet, in which case everyone would accuse them of copying Loki, so it was a no-win scenario.