Every Marvel character who makes the leap from page to screen undergoes the sharp and judgemental eyes of comic book fans. When a beloved niche icon turns out to be radically different in the MCU, fans are often far from pleased with the character's new depiction.
However a character makes their way into the MCU, their on-screen appearance will be the one most people are aware of. The number of comic book fans pales in comparison to the fanbase of Marvel's cinematic efforts. Though fans of both are extremely common, there are tons of film-only fans who have never even considered picking up a comic book.
For the uninitiated, Mr. Knight is one of many alternate personalities living within the body of Marc Spector. While the Disney+ series turns the iconic suit into a powerful tool that Marc can activate at a moment's notice, Moon Knight is typically depicted as one of Marc's separate identities. Marc has Steven and Jake, as he does in the show, but Moon Knight is another living being in his brain. Mr. Knight serves as a more respectable version of the costumed hero. When he needs to operate alongside the police, probe others for information, or solve crimes with more nuanced methods, Mr. Knight is the one in charge.
The comic book iteration of Marc Spector operates as a team, slotting in whichever figure is necessary for the scenario. Steven is the mild-mannered everyman, Jake is the street-savvy wise guy, Marc is the ringleader, and Moon Knight does the actual superhero work. Mr. Knight seems to be an affectation Marc can choose to apply to the standard Moon Knight costume. It provides subtlety and allows him to fill a more intellectual role. No one seems to be interested in talking to cloaked vigilante Moon Knight, but svelte consultant Mr. Knight is a social dynamo. Fans love his slick appearance and stellar action scenes. Mr. Knight leads one of the most well-loved action setpieces of the comics' entire run, in which he single-handedly defeats an apartment building full of enemies like a one-man The Raid: Redemption.
The Disney+ iteration of the character is completely different and operates on different rules. Though Steven and Marc come together by the end of the season, they aren't allies for the majority of the series. They fight for control of the body and violently disagree with each other's methods. When it becomes clear to Steven that his alter ego is capable of summoning a super-suit, he attempts to do the same. Subsequently, he gets the Mr. Knight outfit. Though it's visually perfect, it isn't anything like the comic book iteration of the character. Steven remains frightened and inexperienced as he commands the Mr. Knight facsimile, almost creating the opposite of his comic book counterpart.
The first appearance of the Mr. Knight suit in the series feels like a joke at the expense of fans. Many were thrilled to see the reveal of the perfect costume in the posters and trailers, but the fact that he was largely a comic-relief character felt like a deliberate bait-and-switch. Mr. Knight really isn't in the series, only his costume makes an appearance. Theoretically, if the show gets a second season, Mr. Knight could come into his own as a useful force, but it certainly didn't live up to its source material in his first appearance. The reaction to Mr. Knight, however, was only one symptom of a larger issue with the series. Fans of Moon Knight's comic book iteration were disappointed by the less violent take on the character overall.
Marvel has a long-running problem of undercutting itself with ironic humor. The Mr. Knight controversy feels like the apex of the issue. Unfortunately, Disney is regularly attacked by those who claim that they are censoring fans' favorite comic books. Moon Knight regularly stars in unabashedly violent stories, but the Disney+ edition hides most of its nastier elements in flashbacks. Fans got to see Marc's many past victims torment him, but many wanted to see him rack up that body count. There is an argument to be made for treating Moon Knight the way Fox treated Deadpool and insisting upon an R-Rating. Mr. Knight is only one part of this issue, but it is an interesting example.
There's nothing particularly appealing about adding additional blood and violence to superhero stories, but the resistance to doing so is also a problem. Disney doesn't care whether more visceral action better fits the character, they care that a higher MPAA rating would hurt sales. Unfortunately, Mr. Knight, and Moon Knight as a whole, suffer from being part of the MCU's firm PG-13 mandate. Fans may never get to see an unadulterated take on Marc Spector because the MCU simply doesn't see the purpose of an R-rated superhero story that isn't Deadpool.