J.J. Abrams originally wanted Palpatine to return in Star Wars: The Force Awakens as a clone. Disney was quick to make Star Wars: Episode VII after they bought Lucasfilm in 2012. Three years later Disney released the first film in their sequel trilogy, which introduced a new group of heroes and a new villain, while also bringing back characters from the original trilogy. Disney wrapped up their sequel trilogy as well as the Skywalker saga last year with the release of Star Wars: The Rise of Skywalker.
While the film brought back the main characters from the sequel and original trilogies, fans were shocked to hear that Palpatine was returning from the grave. Fans were excited to have Ian McDiarmid back in his iconic role, but a little confused on how he was alive after he seemingly died in Return of the Jedi. Moviegoers were expecting to get an answer in The Rise of Skywalker, but the only explanation given was that Palpatine's line from Star Wars: Episode III- Revenge of the Sith: "the dark side of the Force is a pathway to many abilities some consider to be unnatural." Many were unsurprisingly not satisfied with this explanation, but J.J. Abrams' original plan was going to be a lot different.
In the most recent addition of Cinefex (via: Comicbook), it was revealed that Abrams not only wanted to bring the Sith lord back in The Force Awakens but would have explained that Palpatine was actually a clone. Visual effects supervisor Roger Guyett explained Abrams' original plan in Cinefex, which can be read in his statement below:
"Ian was such a major part of the original films. J.J. wanted to bring him back to reveal that Palpatine wasn't completely destroyed in Episode VII. He created a clone of himself and, with the help of Sith loyalists, rebuilt himself to a fragmented and unstable state. When Kylo meets him, Palpatine is not fully formed, and he relies on tubes and mechanics, moving around this Sith laboratory on a mechanism that Kevin Jenkins designed. He has the spirit of the Sith, but he's trapped inside a body that's incomplete."
The return of Palpatine was one of many things that people criticized The Rise of Skywalker for. Many felt that the story was cramped and rushed with everything Disney tried to pack into The Rise of Skywalker's two hour and twenty-two minute runtime. This left fans with several unresolved storylines from the previous films as well as many incomplete or unsatisfying story arcs. Due to the backlash of Star Wars: The Last Jedi, The Rise of Skywalker also seemed to retcon a lot of what its predecessor set up.
Overall, the biggest complaint many had about the sequel trilogy as a whole was that the story felt very disjointed because of how many people had their hands on the three films. If Abrams had directed all three films or at least written the whole trilogy, it would have felt like a much more cohesive story, and Palpatine's return could have been more natural. The novelization of Star Wars: The Rise of Skywalker did recently confirm that Palpatine was a clone, but it's unknown why this plot point wasn't used in the film or why Palpatine didn't just return in Star Wars: The Force Awakens. That being said, many fans complained that The Force Awakens felt like a remake of the original Star Wars, so bringing Palpatine back may not have been the best decision.