Nearly every film has incurred some sort of backlash for at least one of its casting choices, though the specific reasons differ across roles, and nearly every one of these choices ended up being extremely well-received once they were actually seen in action:
- Robert Downey Jr.'s well-publicized history with drug abuse, making him a liability on-set and box-office poison once his films were released, were still fresh in everyone's mind when he was cast as Tony Stark. It was assumed his drug-fueled antics on- and off-screen would continue.
- Chris Evans wasn't considered adequate to play Captain America because most of his previous roles generally were too silly, and his base-breaking previous stint as the Human Torch in the poorly received Fantastic Four (2005) movies (a franchise outside the MCU) was still a fairly recent memory when he was first announced.
- Chris Hemsworth was either not big enough for Thor (Thor is stated in the comics to be 6'6",note while Hemsworth is a measly 6'4"note ) or a no-name outside of Australia. Tom Hiddleston was seen as similarly random. See here
for a quick dose of Hilarious in Hindsight, including coments hoping that the filmmakers "put the money they saved in casting straight to special effects." - Scarlett Johansson wasn't Russian or a natural redhead, didn't do an accent, and wasn't the initial choice (being a replacement for Emily Blunt), to the point one article reporting her casting speculated that she accepted the role for "lousy lowball money" (again, Hilarious in Hindsight) so she was initially dismissed as being cast purely for Fanservice reasons.
- People were initially opposed to Mark Ruffalo as Bruce Banner due to not being Edward Norton or looking anything like him, and being more famous for serious dramas than blockbuster films.
- Samuel L. Jackson and Idris Elba were black actors playing traditionally white characters, the latter of whom is based on a Norse deity described in one poem as "the whitest of the gods". However, Ultimate Nick Fury is black and explicitly based on Jackson (who agreed to the use of his image as long as he got first crack at playing Nick Fury on the big screen), while the Norse gods in the MCU are Sufficiently Advanced Aliens.
- Jeremy Renner as Hawkeye disappointed many fans hoping for Josh Holloway. Others considered him too old or ugly for the role and not looking anything like the character from the comics.
- Chris Pratt (Star-Lord) and Paul Rudd (Ant-Man) were primarily known for their comedic roles, not their ability to be action leads.
- Dave Bautista (Drax) was a wrestler with no acting experience.
- Elizabeth Olsen and Aaron Taylor-Johnson had gotten some of this when they were cast as Scarlet Witch and Quicksilver due to them not sharing any of the characters' ethnic background (Eastern European/Jewish/Romani), looking rather young compared to their comic book counterparts, and being picked over popular Internet fan picks.
- Charlie Cox as Daredevil disappointed those who wanted Michael C. Hall. Others were skeptical as he was fairly unknown, and those who did know him knew him best as pretty-boy Tristan Thorn in Stardust.
- Krysten Ritter as Jessica Jones originally got this reaction for not looking much like the character and being considered too skinny and unimposing to play a superheroine.
- Not as extreme as the other examples, but there was some backlash against Chadwick Boseman being cast as Black Panther, as Chiwetel Ejiofor was an extremely popular fan pick for the role. Others thought Boseman was too obscure, didn't look regal enough, or was too young to play the character, even though he was approaching 40 at the time he was cast.
- Chiwetel Ejiofor as Baron Mordo also caused its own share of baffled WTH reactions due to being a Race Lift.
- In addition to a Broken Base over whether Iron Fist should've undergone a Race Lift or not, Finn Jones' most famous role is as the controversially Camp Gay Dandy Loras Tyrell on Game of Thrones. There was also the question of whether he had the necessary martial arts and multilingual backgrounds expected for such a role.
- The public became so used to Dawson Casting in regards of Spider-Man on film that when Tom Holland was cast as Peter Parker many people complained about him looking too young and wanting someone more mature-looking, even though at 19 he's still older than Peter is supposed to be.
- The notoriously controversial decision to cast the white Tilda Swinton as the Asian Ancient One.
- Brie Larson is significantly younger than Captain Marvel is portrayed as being in the comics, leading some fans to accuse Marvel of ageism against female actresses.note Like Boseman as Black Panther, Larson was also chosen over some popular Internet fan choices like Katee Sackhoff, Ali Larter and Charlize Theron (none of whom were officially in the running with Marvel to begin with).
- Michael B. Jordan as Erik Killmonger was met with a mixed reaction given his appearance and acting history. Many detractors feel that Jordan lacks Killmonger's large and intimidating physique as depicted in the comics and his previous portrayal of Johnny Storm in the infamous Fantastic Four (2015) has only heated arguments about his acting ability. However, Jordan's defenders have argued that he is a very talented performer despite not resembling the character with many citing his performance in Creed, and that the MCU has a reputation for redeeming actors from bad comic book adaptations. note
- Since the Runaways cast was announced, there has been much griping about how teenager Allegra Acosta looks too old to play Molly, who is explicitly prepubescent when the series begins.
- Mahershala Ali as Blade got some questions, as while he's a fantastic actor whose appearance in Luke Cage (2016) was already very popular, he'll also be in his 50s by the time the first movie is made, raising serious questions about how long he can last in the physically demanding role. And there are some disappointed that he's not Wesley Snipes.
- Tony Revolori as Flash Thompson was this for many people. Ethnicity aside, it's hard to take him seriously as a bully when he looks like somebody Peter Parker could have knocked flat even before he got bitten by the radioactive spider. It does fit with the character's Adaptation Personality Change, though; his MCU counterpart is a Nerdy Bully rather than a Jerk Jock stereotype.
- Xochitl Gomez being cast as America Chavez in Doctor Strange in the Multiverse of Madness was met with some skepticism. The actress was 15 when the movie was being filmed, while America in the comics is old enough to attend college. There was also some ire cast to her looks, as Gomez is quite small while Chavez in the comics tends to be a buff brawler, and Depending on the Artist is sometimes indicated to be Afro-Latina.
- The announcement that Cassie Lang would be portrayed by Kathryn Newton in Ant-Man and the Wasp: Quantumania was met with this reaction for some. While Newton is a respected and well-liked actress (her repertoire including films such as Lady Bird and Pokémon Detective Pikachu), many people were disappointed that the lesser-known Emma Fuhrmann would not be returning as Cassie instead, as her brief, but emotional reunion with her father in Avengers: Endgame was highly praised. There’s also a number of people disappointed in the recast purely because Fuhrmann wasn’t informed about it privately beforehand, and instead learnt about it at the same time as the rest of the world.
