What Could Have Been / Joker (2019)

• Leonardo DiCaprio and Bill Skarsgård were considered for the role of Arthur Fleck before the casting of Joaquin Phoenix.
• Alec Baldwin and Viggo Mortensen were approached for the part of Thomas Wayne before Brett Cullen was cast. Baldwin turned down the offer due to scheduling commitments to Motherless Brooklyn.
• Shailene Woodley, Gugu Mbatha Raw, Dakota Johnson, Aja Naomi King and Mary Elizabeth Winstead were considered for the role of Sophie Dumond before the casting of Zazie Beetz. Winstead would later go on to portray Helena Bertinelli in Birds of Prey set within the DC Extended Universe.
• Frances McDormand was offered the part of Penny Fleck before Frances Conroy was cast.
• In a case of what could not have been, Phoenix had been in talks with Marvel Studios to play the titular Doctor Strange after Benedict Cumberbatch initially turned down the part due to scheduling conflicts, but backed out due to his reluctance to take on a multi-picture deal. Presumably, had he not been so reluctant, we wouldn't be getting this film (or at the very least, someone else would be taking on the role).
• Todd Phillips pitched the movie as having a new label for DC Films that specifically focused on Darker and Edgier, non-canon stories to their shared universe, but Warner Bros. deemed that it was too early to think about doing that and released it under the standard DC Films banner instead. Given the film's success, however, Phillips' plans for the label are seemingly materializing.
• Joaquin Phoenix wanted to gain weight for the role, having lost too much weight for previous roles and also wanting to look the way a person like Fleck realistically would look. Todd Phillips overruled him and Phoenix reluctantly lost weight.
• According to the aforementioned Content Leak, an earlier version of the script had a different story arc in mind for Sophie. Arthur originally did go out with her a few times, but she only did so out of pity, and she was romantically-involved with someone else. When Arthur discovered this, he went on an extended, borderline-misogynistic rant to her face, before telling her to watch Murray Franklin's show on the fateful night. This version of the story makes it clear that he didn't kill her, as she's shown watching the show with her child.
  • Another element from the leaked script that didn't make the cut was a scene where Arthur originally told Sophie a story during a date, explaining that he cut a slight smile onto his face as a child to scare off bullies. The scene would get a call-back at the end of the film, where Arthur, now the Joker, would have used a glass shard from the car wreck to carve those wounds open again and spread them even wider in front of the crowd. This idea was ultimately scrapped, and Arthur instead paints the smile on his face with his own blood.
  • The original script leak had a slightly different ending. After Arthur kills Murray, he escapes the studio. The riot occurs but in this version the rioters break into Wayne Manor, dragging out Thomas and Martha Wayne and executing them. Bruce, while this occurs, hides from the rioters and is found by Alfred the next day. Arthur eludes the police for a few days until he shows up at the Waynes' funeral and he is immediately seen. Arthur is chased and tries to flee but during the process is hit by a car and captured by the police.
• The script was going to have the song "Bennie and The Jets" in the movie but for some reason this was changed.
• Martin Scorsese had hoped to direct the film for a few years, but ultimately declined as while he loved the whole idea of the Arthur Fleck character, his lifelong distaste for comic book movies meant he was never comfortable with how the movie would have to end with him becoming the Joker, and figured the comic fans deserved to have it be made by someone whose heart was in that ending.
• An alternate ending intended for the film had Arthur telling the joke he was thinking of to his psychiatrist in Arkham: that he had killed Thomas and Martha Wayne himself and left Bruce Wayne to cry before turning back and killing the boy. The ending was changed because Bruce's death would mean that Batman will never come to exist in the film's universe.
• Allegedly, WB was incredibly reluctant to greenlight the film at all, since it was a Batman-related film that didn't have any merchandising potential.