10 Actors Who Should Play Doctor Who (But Won't)
6. Michelle Gomez
Okay, hear us out: how much fun would it be if the Doctor was an actor who had previously played the Master?
It would be hilarious and just so confusing for everyone, and would provide some serious insight into the Doctor's psyche if they wanted to go in that direction. Michelle Gomez is an incredible actress, and it's easy to imagine her bringing as much delightful madness to the table as the Doctor as she did with the Master (same goes for Sacha Dhawan and John Simm too).
It would also be really interesting if they brought back an old character who interacted with her as Missy, and have her trying to convince them that she's not evil. It's easy to imagine that being one of the funniest storylines in the history of the show.
At any rate, despite Doctor Who's history of reusing actors, this doesn't seem likely to happen - at least, not in a full-time capacity. But a one-off episode where the Doctor temporarily switches faces? That could work, and would any face have more narrative potential than one belonging to their arch-enemy?