One of the delights of Doctor Who (or irritations, depending on how you feel about a particular one) is recurring characters. The tradition began decades ago, primarily out of necessity when the production team decided to take the show in a new direction and strand the Doctor on Earth. The team of humans at UNIT with whom he worked for the next several years became honorary TARDIS crew, even though most of them rarely (if ever) set foot inside the TARDIS.
To this day, Brigadier Alastair Gordon Lethbridge-Stewart (usually simply called “the Brigadier”) is remembered fondly—so much so that his daughter Kate Stewart has followed in her father’s footsteps and become a quasi-regular on the show in her own right. If Nicholas Courtney were still alive, it’s a sure bet they’d be trying to find a way to get him a guest spot.
Since the show’s return in 2005, others have wormed their way into fandom’s collective hearts. Regardless of how you might personally feel about either of them, it’s hard to deny that Capt. Jack Harkness and River Song each have a large following. River has appeared in a whole series’ worth of episodes (thirteen of them) over the years, and though Jack only appeared in eleven episodes of Who, he also got three (or four, depending on how you count) series of his own show.
Whenever popular non-core characters crop up that often, fandom begins speculating about (and in some quarters, clamoring for) those characters’ returns. After an interview published last month in which Moffat admitted he was open to bringing either Jack or River back—provided the stories called for it—I’m sure the lobbying engine will kick into overdrive (as if fan input ever actually affects Moffat’s decisions).
