Here's why Steppenwolf, portrayed by Ciarán Hinds, was widely accused of being a one-dimensional character and lacking any real motivation other than the generic wanting to take over the world trope. The fact that Steppenwolf was a computer-generated creation also attracted plenty of criticism and the effects themselves were roundly panned, adding to the general sense of disappointment.
For many who felt underwhelmed by Justice League, there is still a glimmer of hope: a cut of the movie by original director, Zack Snyder. The fabled concept art, give fans a vague idea of what Justice League was originally intended to be.
In the never part of the Justice League movie, even before he departed the project. But why did he change it when Snyder has a strong affinity for the design?
The primary reason for this is likely the backlash against Batman v Superman. Much like Justice League, the long-awaited cinematic clash between the Caped Crusader and Krypton's favorite son was not at all well-received and one of the most frequent jibes regarded the film's uber-dark tone. This was famously highlighted in the Ryan Reynolds' antihero hilariously quips, "you're so dark. Are you sure you're not from the DC universe?"
As a result, Warner Bros. sought to make Justice League a slightly less gritty affair and it was reported last year that the studio scrapped a Parademon transformation scene because they deemed it too "scary." Justice League's script was also given the rewrite treatment following the Batman v Superman debacle because Warner Bros. wanted a generally more optimistic feel to the movie. Since the original, monster-like version of Steppenwolf didn't even make it into the Snyder Cut, it's likely that this design was scrapped as part of the post-BvS attempt to ensure Justice League had a less dark tone compared to its predecessors.
In hindsight, those efforts proved futile, as the DCEU's fortunes continued to struggle, and since Zack Snyder was evidently fond of the original Steppenwolf look, it could be argued that the villain might've received a more positive reaction had the director's original vision been retained - a truth that holds true for much of Justice League.