Paramount+'s streaming channel Star Trek movie, Section 31, did little, if anything, to move Emperor Philippa Georgiou [Michelle Yeoh] toward redemption even though there was supposed to be a redemption arc. That wasn't evident in the movie. Star Trek: Discovery did more to show there was another side to the evil Emperor than Section 31 did, and now that the movie has actually done her a disservice, she needs another shot at becoming the person Michael Burnham [Sonequa Martin-Green] always believed she could be. That could be achieved with a Discovery movie.
The entire Discovery crew is in the 32nd century, and that century didn't agree with Georgiou; however, a brief sojourn back to the Discovery could and should work for the former Emeperor. Yeoh's character was at her best aboard the ship and with Burnham, not with strangers who she is supposed to work covert missions with.
While Section 31 showed how Georgiou became the Emerpor of the Terran Empire, there was really no explanation as to why such a battle was needed to choose an Emperor. We didn't know what happened to the prior Emperor, why a new one couldn't just be chosen by the former Emperor, and if someone could simply refuse to participate in the battle to become the new leader. Those, to me, are important aspects that shaped Georgiou.
In addition, the Georgiou in Section 31 had none of the softness that was starting to show in her in Discovery. There was no mention of her life before her nightclub nor were there flashbacks to what she'd left behind. It was as if Georgiou had put it all out of her mind and never thought of her past at all. We don't even know if the opening scene of Section 31 was a flashback.
That's why Georgiou needs to return to Discovery or, worst case scenario, some of the members of Discovery need to meet in her timeline. I think it would be more probable for the Emperor to return to the 32nd century. She wouldn't be able to stay long, but certainly long enough for a movie that helps smooth out the rough edges. I'm not saying make her weak or docile, but there needs to be a reason for fans to root for her, why we should care if she is the victor in future battles. Going back to Discovery could do that for her. Maybe she learns through a time traveler that Burnham has been seriously injured, or she discovers something that could affect the future and knows she needs to alert the Discovery crew. Whatever the reason, a trip back to Discovery would fix what Section 31 broke.