The Pirate Planet is roughly the point where Doctor Who starts borrowing shamelessly from Star Wars - Landspeeders, wise monk types and K-9 all in a single episode.
Which naturally makes me think what other classics might have had a similar effect? Not a crossover, but borrowing motifs and integrating them into the Whoniverse.
We’ve already seen how Quatermass and The Avengers lead to the UNIT years, and the imprint of Buffy and Farscape on the Davies era and Harry Potter And The Time Of Moffat, so what other classics of the genre might the show have tried on for size?
Straightforward space adventures, with a wide variety of story styles built in, including adaptations of classic short stories and episodes by genre legends. Hit here during the gap between Troughton and Pertwee. Really taking advantage of colour. Adventures like the Peladon serials could show a bit of a Trek-ish influence, as does the increasing importance of the sonic screwdriver and perhaps the goateed recurring villainy of the Master. An alien companion could be interesting, but the show started to play up the alien-ness of the Doctor instead.
Example from the Doctor’s log: The TARDIS arrives on a planet home to near-humans enslaved by a “god” who turns out to be a mad computer.
The show didn’t taken on Indy at the time, but it nearly happened in 1993 - the unmade Amblin Doctor Who film scripts were a bit too close to home for Steven Spielberg, one featuring the Doctor and Amelia Earhart chasing the Master across human history looking for The Jewels Of Time, the other starting with the Doctor unearthing an ancient scroll on an archaeological dig (on Gallifrey) and features tomb robbing in ancient Egypt and a companion from the 1940s.
Example following the red line on the map: Nazis have discovered an alien artefact and intend to use it to conquer the world!
Star Trek: The Next Generation
Doctor Who largely reacted to this by emphasising the elements they didn’t have in common, the Seventh Doctor and Ace having adventures in the past and present with a lot of horror and comedy. But the early and minor examples of arcs mixed in with standalone stories, and the attempts to juggle a large and diverse cast, had a bit of an influence down the road. Of course, a British stage actor defeating alien menaces with dialogue works too... Stumped? Consider some of the plot hooks from TNG Season 8, perhaps with a pinch of salt.
Example from the Doctor’s log a century later: A distress call from a colony planet leads to a mystery as the TARDIS crew find the facility deserted - except for its children...
The X Files
Hitting big during the early wilderness years, this could have seen a return to Earthbound paranormal mysteries and horror, with a lot of arc episodes, sinister MIB types, and of course long narrow torch beams.
Example file: Somewhere in the Home Counties, reports of strange lights in the deep dark woods. Is there really an alien here, abducting people and performing experiments, or is the threat closer to home?
One of the most RPG-friendly settings around, this space opera happening now would be a good starting point for a modern UNIT style game, with squaddies fighting malign space gods on distant planets that have a perfect excuse to have quarries everywhere and humans instead of aliens. Villainous aliens taking people over with telltale glowing eyes is a much-loved trope that could get another airing too.
Example field report: The Pyramids Of Mars. ;)
Battlestar Galactica (2003)
Sharing influences from the likes of Star Wars and Aliens, the modern reboot emphasises the threat of an implacable cybernetic enemy, the chaos of a disorganised escape, the paranoia of infiltration, chances for heartbreak and doomed heroism... I can imagine a series about the Time War looking quite like this.
Example flight log: The TARDIS finds a 44th Century colony besieged by Daleks who appear to want something other than simple extermination. Do they have a plan?