So I lied before. I do have a few thoughts about the finale, which (of course) have to do with past episodes. Let's start with Tim Shaw's planet collection. (But if you ring in the next 15 minutes, we'll throw in this set of eight asteroids for free!) There's nothing new under the sun and all that; for instance, that scene where Graham and Ryan duck while surrounded by sniperbots which then shoot one another: I can think of at least four previous adventures that pulled some version of that trick.
And they've done the planets in stasis notion before as well, back in 1978, in an adventure called The Pirate Planet. This ep's reputation has, I think, improved in the intervening years. The plot is actually very clever and is quite funny to boot. Despite this, it was one of only five adventures not to get novelised at the time. The reason: the BBC couldn't afford the scriptwriter's fee to adapt it. It was one of three stories written for Doctor Who by Douglas Adams.
Before The Hitchhiker's Guide to the Galaxy was produced, Douglas Adams was involved in Doctor Who. He was script editor for a year, and wrote three scripts for the show. One, Shada, was cancelled after a strike stopped production halfway through. (It was released last year with the addition of some animated sequences.) Another, City of Death, is regarded by many (including me) as one of the greatest adventures ever. It has an ingenious plot, a brilliant Part 2 cliffhanger, a fantastic guest cast (Julian Glover and Catherine Schell), Tom Baker and Lalla Ward in love in Paris, and some of the funniest scenes the show's ever done. Oh, and a cameo by John Cleese and Eleanor Bron. [link] Seriously, if you get the chance, watch this adventure.
Then there's The Pirate Planet. It's a very clever notion. The Captain (a space pirate, complete with robot parrot), has engineered an entire planet to teleport around the galaxy. It's completely hollow; he uses it to engulf other planets and strip them of their mineral wealth (killing the entire population in the process, if it's inhabited). The Captain then compresses the planet's remains to the size of a basketball and holds it in a stasis field. He's done this to 22 planets so far.
Tim Shaw, of course, is doing much the same thing. Compare the dialogue between the two adventures when the Doctor finds out. The Battle of Ranskoor av Kolos:
"Planetary genocide... Tim Shaw, I didn't like you before but now... Make them stop, you're breaking every known law in the universe."
And The Pirate Planet:
Captain: "The whole system is so perfectly aligned by the most exquisite exercise in gravitational geometry that every system is balanced out within itself. Which is why we can stand next to billions of tons of super- compressed matter and not even be aware of it. With each new planet I acquire, the forces are realigned but the system remains stable."
The Doctor: "Then it's the most brilliant piece of astro-gravitational engineering I've ever seen. The concept is simply staggering... Pointless, but staggering."
Captain: "I'm gratified that you appreciate it."
The Doctor: "Appreciate it? Appreciate it! You commit mass destruction and murder on a scale that's almost inconceivable, and you ask me to appreciate it?! Just because you happen to have made a brilliantly-conceived toy out of the mummified remains of planets!"
Captain: "Devilstorms, Doctor! It is not a toy!"
The Doctor: "Then WHAT'S IT FOR?! Huh? What are you doing? What could possibly be worth all this?"
The answer is so the Captain can escape his current enslavement by his nurse, but that's not important here. What is important is that this is genocide on a massive scale. In one script, the Doctor understands this. In the other, it sounds like she's considering blocking him on Facebook. I would posit that this is a problem for a series that tends to rely heavily on the Doctor carrying moral authority, a notion I'd like to explore further in a future post.