Nobody is quite sure what to expect from Justice League now that an entirely new director is handling the film's reshoots and post production work. However, star Gal Gadot isn't worried about the effect the changes will have on the final product. While many are concerned, or excited, about the ways that Joss Whedon could potentially change Justice League, the actress behind Wonder Woman clearly doesn't see the changes as a big deal. According to Gadot...
Look. Joss, to my understanding, was Zack's choice to finish the movie. And the tone can't be completely different because the movie was already shot. Joss is just fine-tuning.
Exactly what Joss Whedon is doing as the emergency holographic director on Justice League has been a major topic of speculation. Reports have come out that reshoots did a lot to change the tone of at least one character in the film, but Gal Gadot's comments to Rolling Stone note it would be difficult to change the film's tone without reshooting the entire movie. Those comments certainly make sense. There's only so much that can be done with the limited time and money allotted to the reshoots. At the same time, the simple fact that Joss Whedon isn't Zack Snyder also can't be ignored. As much as Whedon might be trying to simply fine tune Snyder's movie, he can't read the man's mind, and so some of Whedon's own style and perspective seemingly have to become part of the finished product as a result.
While Gal Gadot may see Joss Whedon as simply fine-tuning, her co-star Ben Affleck seemed to feel that Whedon was taking a stronger position as the current director of Justice League. Affleck called the film an "interesting product of two directors" which certainly sounds like he saw Whedon doing more than simply polishing up somebody else's work. The difference in opinion could simply have to do with who was more involved in reshoots. Perhaps most of Wonder Woman's scenes didn't end up on the reshoot schedule and so Gal Gadot didn't see a lot changing, while others did.
At least one recent report claims that Justice League's ending was changed as part of the reshoots which, while not necessarily indicating the change in tone that Gal Gadot mentions, certainly would indicate that Joss Whedon is making significant changes to the film as a whole. He's almost certainly not making these changes unilaterally. Zack Snyder is still a producer on the film and is almost certainly being kept in the loop on what's happening, so any changes likely have Snyder's OK, but if that ending rumor is true, a change in the ending is probably not just fine-tuning.
Hopefully, once Justice League arrives in theaters, we won't be able to tell the difference between which scenes were shot by which director. That will be the sign that the two directors were able to really work together to create a single, hopefully fantastic, film.