Board Thread:Arrow discussions/@comment-807326-20171117030359/@comment-27700324-20171201070322

SeanWheeler wrote: If Iris was planned to die at the beginning of Season 4, that would be a huge insult to the Savitar arc. Why would WB let them spare Iris from Savitar and then kill her off at Season 4? Season 4 started only a month away from Justice League's release and we were only six episodes in. The Season 3 finale is the only time they could have killed her. She was set to return as a regular, not a guest star. If Iris's scene was kept, she would have been shown in both TV and movie like Barry. The success in saving Iris proves it. Except they were planning to put her into it only towards the end of the season. They already written the episode where they save her. So WB probably said "Well kill her off in the next one".

The CW probably gave her the position of leader of the team as a good final send off thing for a few episodes, but then they cut her out of the movie and Iris stayed.