Zack Snyder's Superman reboot Man of Steel took on the dual challenges of re-introducing one of the world's most iconic superheroes for the modern age, while also building the foundation for an entire DC movie universe. Seven years after its release, the debate about Man of Steel is still going on - which is testament to the impact and power of Snyder's vision. There is no shortage of DC fans who insist that Snyder ruined Superman with his somber and violent depiction of the character. At the same time, there equally many fans who insist that Snyder made the definitive version of the character, for modern times.
It Expands The Superman Metaphor
The greatest thing that Man of Steel does (especially early on in the film), is to expand the Superman metaphor to include entire groups of people who may have previously felt left out of it.
Man of Steel's first act explores Superman/Clark Kent's turbulent childhood from the angle of an outsider who struggles to find acceptance in the social order, constantly searching for his place and true identity. The metaphorical implications of Snyder's approach are bold and powerful - whether it's the literal (and figurative) "closeted" life young Clark must live while growing up in Smallville, or his dilemma of being a literal (and figurative) undocumented alien, trying to avoid detection in a xenophobic American order.
Best of all, in the midst of expanding Superman's relevance to touch upon the experiences of more disenfranchised peoples, Man of Steel never loses sight of that original thematic thread from both the Superman comics and the iconic Richard Donner films. The idea of being trapped in a small town that stifles your full potential, and having to show restraint and patience until a greater destiny can be achieved, is a part of the Superman mythos that any adolescent or teenager living in the world can still understand.
Because of Man of Steel, the themes behind Superman are more open and diverse than they ever have been.
It Grounds the Mythos
Superman's origin story is one of the most famous and iconic modern myths around, but that golden version of the story that fans used to hold onto with such reverence became outdated, and (for many of the groups of people described above) irrelevant.
That worn-out notion of "Classic Superman" and his story became apparent in 2006, when Warner Bros. tried (and failed) to cash-in on Donner Superman nostalgia with Bryan Singer's Superman Returns. That film stalled, while the year before, Chris Nolan's Batman Begins proved that superhero movie fans were hungry for something more modern and serious from their DC icons.
Well, Man of Steel takes all the of the various elements of Superman's character and origin (American, extraterrestrial, superhero) and as stated, makes them feel cohesive and grounded in a way that a wide variety of modern viewers can believe and relate to.
Best of all, Man of Steel goes through great pains to show how Superman - as an imperfect being like the rest of us - starts the journey toward becoming the noble icon he eventually does, instead of simply stating that he's inherently so good he can never do wrong.
It Reveals The Hero's Complexity
Man of Steel takes the bold approach of truly exploring the full character of Superman, as both a homegrown American icon and an otherworldly figure from an alien culture (with all the religious metaphor in between).
While other Superman films (like Superman I and II) also explored the dual cultures that make Kal-El/Superman who he is, Man of Steel delivered everything from his Kansas upbringing and Americana values, to a full-on alien invasion, and made it all feel as if it could believably and cohesively exist within our modern world and sensibilities. The reboot makes Clark/Kal-El feel more relatable and real, by depicting him as being flawed as the rest of us.
Some viewers like to criticize the "brooding Superman" or "killer Superman" the film depicts; however, by exploring Clark Kent/Kal-El's internal struggles and insecurities before he finds his way to a nobler heroic outlook, Man of Steel earns Superman's heroism in a way that few other versions of the character have.
It Innovates (And Not Just Recycles)
The big thing that went wrong with Singer's Superman Returns was that it tried to simply recycle the nostalgia and iconography that Richard Donner created with his Superman movies. As stated, reaction to Superman Returns proved that we could 'never go home again' to the era of Superman mythos that the Donner films had existed in. The post-9/11 world was a much different place and therefore needed a different Superman for the times. Man of Steel keeps a lot of the Superman mythos intact - but it also adds a lot of new elements (or elements borrowed from modern Superman comics) that make the story fresh and new for our times.
From the depiction of Kryptonian culture and the origin stories of Jor-El and Zod; to the limitations of Superman's power and the relationships he has with his two fathers; to the way Lois Lane and Clark Kent are respectively depicted as keen, smart, investigators; Man of Steel creates something new on top of the old foundation.
It's almost funny that the movie gets slammed for changing canon, as comic books, by nature, are platforms of constant change, evolution, and innovation. So if anything, Zack Snyder was simply following in that tradition.
It Sets Up An Entire DC Universe
One thing that is becoming more and more apparent as the DCEU unfolds, is that Man of Steel laid the groundwork for so many other DC Films to come.
Fans know the obvious Easter eggs like the Wayne Tech or Lexcorp properties destroyed in the battle of Metropolis (thereby setting up Batman v Superman); however, MoS also opened the cosmic side of the DCEU with its invasion story; catalyzed an entire shift in government initiatives (metahuman projects, Kryptonain tech influences, and even Suicide Squad's Task Force X), and was the milestone event that ushers in the new "Age of Heroes."
Since its time of release, fans have gone back to Man of Steel with retroactive theories that suggest Aquaman could've been teased in the film (after that oil rig explosion) - along with any number of other Easter egg theories. The bottom line is: Man of Steel introduced the foundation of an entire universe, by first introducing its most powerful hero on a universal stage.
While Marvel may get credit for its connective threads, Man of Steel has slowly but surely established itself as an almost better launchpad than Iron Man was. Best of all: there is still more potential retroactive tie-ins that can (and probably will) be mined from it!
It Still Being Talked About
One of the biggest proofs that Man of Steel is milestone cinematic accomplishment, is that we're still talking about it, over half a decade later. Various decisions and scenes in Zack Snyder's film (like Pa Kent's death, or Superman killing Zod) have never stopped being debated within the fandom. Love or hate the decisions, the impact of the movie is undeniable. Some say the test of good art is how long it stays relevant - Man of Steel is still a trending topic, despite being released before trending topics were even a thing.
It Inspired Fan Greatness
The biggest and best thing about Man of Steel is that its unique vision helped inspire one of the most passionate - and now successful - fan movements ever. When Warner Bros. chopped up Snyder's vision for Batman v Superman, fan outcry led to the release of Batman v Superman: The Ultimate Edition, which conveyed Snyder's true vision. That became a major success on home video. When WB fired Snyder from Justice League and used Joss Whedon to finish the film, fans started a multi-year, full-spread media and social media movement get Snyder's version of the movie released. Now, as of writing this, Zack Snyder's Justice League is going to finally be released, and the studios is investing in a massive effort to finish it properly.