The former Doctor Who showrunner wanted to bring back one of the Doctor's most famous adversaries for the show's 50th anniversary.
The final episodes of Doctor Who's most recent season are controversial for many reasons. There's Fifteenth Doctor Ncuti Gatwa's surprise regeneration, the apparent return of former companion Billie Piper as the (maybe?) Sixteenth Doctor, and the fact that the season's Big Bad turned out to be the renegade Time Lord known as Omega. But, one of the most exciting -- and, in turn, frustrating -- twists was the reveal that the mysterious Mrs. Flood, who had spent the better part of two seasons snidely breaking the fourth wall to address the audience throughout multiple episodes, was actually the rogue Time Lord known as the Rani.
A classic Doctor Who villain who hadn't appeared on the main series since 1987's "Time and the Rani," the character had grown rather infamous in the modern era for not returning to the show's canvas. (The characters who turned out to be Madame Kovarian, Missy, and the Fugitive Doctor? All initially speculated to be the Rani by many fans.) But showrunner Russell T. Davies finally pulled the trigger, and Mrs. Flood regenerated (biregenerated, technically) at the end of "The Interstellar Song Contest" into Archie Panjabi, a second version of the infamous Time Lady.
But, thanks to some intrepid fans, we now know that the Rani's return was initially set to happen well before the Fifteenth Doctor era. Apparently, former showrunner Steven Moffat initially planned to bring the character back as part of the show's 50th anniversary celebrations in 2013. Obviously, that plan never came to fruition, but it's certainly entertaining to wonder what might have been.
This news comes courtesy of a Reddit user who, along with some friends, purchased a batch of early draft and/or shooting scripts for a handful of Moffat-era episodes, including "The Angels Take Manhattan," "Time of the Doctor," and "Phantoms of the Hex/The Hider in the House" (the episode that would eventually become "Hide"). However, the early script fans will likely be most interested in is the draft of the mini-episode "Night of the Doctor" that aired in 2013. Notable for finally showing us Eighth Doctor Paul McGann's regeneration and the subsequent birth of John Hurt's War Doctor, the minisode saw Ohila, a member of the Sisterhood of Karn, play a key role in helping the badly injured Time Lord choose his future.