9. Characters Through The Series Need To Return
The Master, Ruth, Captain Jack. Who saw any of these coming back?
After Steven Moffat rested the Master for a few years after John Simm's tenure, Chris Chibnall took advantage of the fan's assumptions that Missy would be the last incarnation of the character for a while, and snuck in Sacha Darwan to terrorise Team Tardis. After a brilliant entrance episode, he was left in an alternate dimension. That can't be the end of him though, and he has to be involved in the finale somehow, perhaps working with the Cybermen.
Moving on a couple of episodes, we were introduced to Jo Martin's 'fugitive' Doctor. There's been many theories since on who she really is (you can check this author's personal opinion here), but she's definitely connected somehow to the Timeless Child mystery, and while we're not expecting all the answers this year, fans would be disappointed to not see her involved in the finale.
Similarly, we need to see a return from Jack Harkness following his extended cameo in 'Fugitive of the Judoon'. Chris Chibnall has gone on record to say Jack won't be back this series, but we all know that showrunners have a tendency to lie.