Zack Snyder Helped Aquaman Director Undo Joss Whedon’s Justice League Changes
Zack Snyder is partially responsible for the changes Aquaman made to Arthur Curry after his appearance in Justice League. Snyder was the original director on Justice League. After the movie's principle production - but before reshoots - Snyder stepped away from directing due to a personal family tragedy. As a result, Avengers director Joss Whedon stepped in to direct the reshoots and changed Snyder's Justice League.
The difference between Whedon and Snyder's approach has been a source of controversy. It's been cited as an underlying reason of Justice League's middling reception and, of course, a group of devoted fans have petitioned Warner Bros. to release "The Snyder Cut" of Justice League. The Snyder Cut may not see the light of day in the immediate future, but evidently Snyder did have a hand in the positive response to James Wan's Aquaman.
The information about Snyder's involvement in Aquaman comes from actor Neil Daly on the Fire and Water Podcast. Daly was responsible for running the test screenings of both Justice League and Aquaman. Daly revealed that Whedon was behind much of Justice League's "teenage boy sexual humor." This includes gags like Aquaman hitting on Wonder Woman while under the influence of the Lasso of Truth. Wan didn't want this approach in Aquaman. Daly explained:
We could have gotten a whole movie about Aquaman basically fawning over Mera the whole time and making all kinds of dirty jokes and things like that and they really had to get away from that, which is all what Whedon had done, so Snyder had a little bit of an influence on Aquaman. James Wan was showing Zack Snyder - against the studio's wishes - cuts of the movie and early test screenings and storyboards to make sure that they're on the same page with what he originally wanted and Snyder gave his blessing of approval, bringing it back to what he wanted all along.
In the final cut of Aquaman there's certainly a romance between Aquaman and Mera. Jason Momoa's Arthur Curry shows obvious interest in Amber Heard's Mera even when he doesn't want to accept her mission to become the King of Atlantis. Daly is right, though, that the tone of their interactions is quite different from Arthur's attitude in Justice League. Most of Arthur's interactions with Wonder Woman in the superhero team-up is objectifying her or otherwise commenting on her physical beauty. In Aquaman, Arthur isn't anywhere near as boisterous. Most importantly, he never objectifies Mera despite being obviously attracted to her.
This calmer (and arguably more likable) Arthur is apparently the vision that Snyder had for the character all along, though there's only Daly's word for it. Snyder never really had much of a chance to deliver his version of Aquaman in the DCEU. Snyder did cast Momoa and the actor has been clear about his gratitude toward Snyder. However while Momoa is in Snyder's Batman v. Superman, he only has a wordless cameo. If Daly's comments can be taken at face value, it seems a lot of Arthur's depiction in Justice League is down to Whedon, at least in terms of Aquaman's humor and/or his relationship with women.
Arthur's relationship with Mera isn't the main reason that Aquaman has made over $1 billion and has received wide critical acclaim. It certainly helps, though, and it's hard to deny that Aquaman and Mera are one of DC's biggest current power couples. In fact, they might be the only existing one as the future of Lois Lane and Superman is uncertain and a ton of mystery revolves around Wonder Woman and Steve Trevor. Wan's efforts shouldn't be discounted in all of this, but Snyder's involvement in the DCEU isn't entirely as absent as many believed.
Source: Fire and Water Podcast