Dark Phoenix was originally going to be a two-part film, but Fox changed its mind. Simon Kinberg's directorial debut gave the studio a second chance at adapting Chris Claremont's iconic The Dark Phoenix comic book narrative following the critically-panned X-Men: The Last Stand. Sadly, fans are less than impressed with the contemporary re-telling evidenced by the bad reviews and disappointing box office performance.
It's no secret that Dark Phoenix had a tumultuous production. The film's release was delayed multiple times, as it underwent fairly extensive reshoots, including reworking its whole third act after its ending was supposedly too similar to another recent superhero film now known as Captain America: Civil War. It was also caught in the middle in a major transition with Disney acquiring Fox's TV and movie assets. Despite principal photography starting long before the buyout process began, there was still confusion regarding how to go about the project, especially in terms of mapping out its marketing campaign. Apparently, even before all that happened, there was already a significant change in the film's format as it was initially written to be a two-parter.
Deadline reports that Dark Phoenix was originally planned to be split into two films, but during "late pre-production, the studio changed gears and said it was to be one movie." Kinberg, who also wrote the movie on top of directing it accommodated the studio's request and rewrote the narrative to be just one film. Since X-Men: Days of Future Past wiped out the events of The Last Stand, it was possible to tackle "a rebooted story about Jean Grey ." However "testing Dark Phoenix was a continual headache, and the feature adaptation of Chris Claremont, John Byrne, and David Cockrum’s fan-beloved Dark Phoenix Saga comic was hard to get right."
Aside from Dark Phoenix supposedly being a two-parter similar to the set-up of Avengers: Infinity War and Avengers: Endgame, it sounds like adapting the Dark Phoenix saga was an after thought as well. It's unclear if Kinberg was keen on tackling the story again prior to Fox's decision to condense his narrative to a one-off, but based on the report, it seems like they decided on doing it again because it didn't break continuity. Perhaps the story was always meant to be re-told but not this rushed - and for most viewers, this was the problem. It didn't feel like they have earned the right to do this massive arc because it hadn't been that long since this iteration of Jean Grey was introduced.
The two-film format explains why Kinberg said that the original Dark Phoenix ending would've seen the team split into two - because they would've still had another film that would've hopefully resolve this conflict. It would've been odd if the X-Men franchise wrapped up with a lingering rift between the members, the same way Civil War ended. Sadly, despite restoring peace among the mutants, the film ended up to be underwhelming and definitely an underserved swan song to Fox's X-Men saga.
Source: Deadline
