Since the arrival of the Infinity Saga box set, which collects the first 23 films of the Marvel Cinematic Universe in an ultra-sleek package, fans have been going gaga for some of the behind-the-scenes features, namely ones that spell out alternate story trajectories the MCU could have gone in. One such instance that has gotten a predominant amount of attention is the reveal that director Joss Whedon originally wanted Captain Marvel to appear in Avengers: Age of Ultron. This is very curious material, especially in light of 2019 featuring both her first solo movie, as well as a brief-but-pivotal role in Avengers: Endgame.
For years, it's been known that Carol Danvers' character was included in the script, but a new special feature from the box set enunciates where she would have made her appearance. During the film’s climactic battle, which presented new Avengers members like Scarlet Witch, Whedon planned to introduce Captain Marvel, and he even used a fill-in actor for the shoot. There are a plethora of reasons Marvel chose not to do this, but it’s rather fascinating to think what would have happened to the MCU had Captain Marvel made an earlier debut.
There are two factors one must think about in regards to Captain Marvel and how her introduction changes the status quo of the MCU. For one, she’s the most powerful being in the MCU thus far, and secondly, she’s an adventurer of the intergalactic variety. The Guardians of the Galaxy’s meetup with the Avengers was a fairly slow-burn process that took two phases to happen, but if Carol had appeared in Age of Ultron, it’s logical to think their meetup may have happened earlier.
Captain Marvel also has the ability to traverse galaxies at a rate none of Earth’s other superheroes (thus far) have. Had she been around, she may very well have turned up in Guardians of the Galaxy Vol. 2 to help fight off Ego. While it’s enticing to picture how epic it would be to see Carol Danvers and a full-powered Star-Lord do battle with his evil celestial father, it likely would have been too much, and it also would have downplayed the father-son conflict that was central to the film. Furthermore, Captain Marvel may have then helped Star-Lord return to Earth, which would have obliterated the potential for him and the other Guardians to run into Thor in space in Infinity War.
Of even more concern for story trajectory, however, is that we have to think of how Carol's presence on earth would have effected other movies during Phase Three. Considering how powerful Captain Marvel is, it’s also easy to think that a lot of the villains (even the colossal ones like Dr. Strange’s Dormammu) would have been easily dispatched. Sure, Endgame established that Carol can’t stay on Earth because there are countless other planets that need her help, but this proposed Age of Ultron appearance would have set her up as a team player for Earth's Mightiest Heroes.
Granted, we’ll never know exactly how the gears would have turned if Whedon had had his way, but it’s looking like it was a smart move that the powers that be withheld on Captain Marvel. What made her solo movie so desirable was that it acted as a prequel to the MCU, and it was great fun to see a younger Nick Fury and what motivated him to start the Avengers Initiative. Of further importance, the movie succeeded in fully developing Carol Danvers before she attainted her superhuman abilities, which is integral to the character as she wears a very human face (literally and metaphorically). Plus, after the devastatingly bleak finale of Infinity War, there was a strong emotional component to introducing Captain Marvel afterward. After all, she's the MCU's most powerful hero, which restored faith in fans’ hearts that Thanos would indeed be defeated and all his damage would be undone. (All right, we all knew that was going to happen anyway, but it’s nice to have any sensation of hope right now!)
All in all, we can be grateful that Marvel chose to go in the direction that it did with the character, and while her solo outing had its detractors, her reception was universally positive for Avengers: Endgame. Whedon hasn’t directed any films for Marvel since Age of Ultron, often saying the studio didn’t allow him to make the movie he wanted to. We’ll never know how his intended version would have turned out, but clearly no one seems to be upset about where the MCU has gone since.