“Why do dreams have to fade so quickly?”
Back in the Billie Piper era, I said that companions are the masterstroke of Doctor Who’s formula, and that bears repeating. More so than the villains or weekly story premises, they offer a distinct tone and conflicts, and keep the show refreshed along with the Doctor’s various regenerations. As with anything that upsets the status quo, each one has their supporters and detractors among fans.
Anything can happen on Doctor Who, yet the fantasy only matters when it has fully-fleshed characters to happen to. The Doctor is essentially beyond real damage or threat, but the ordinary people under his care provide the stakes, the heart, and an audience for him to monologue exposition at. Sometimes, the show will ground its adventures when their lives or happiness are threatened. This fantastic trippy episode delves into the subtext of all three characters’ perceptions of one another, and gives insight to the Ponds’ relationship. Amy’s Choice is also a great showcase for the mild-mannered heroics of Rory Pond, who did some deceptively cool stuff in his time on the show.
Moffat had a few troubling pet themes and issues which would wear down his work over time, such as complex reality puzzles, women as plot points rather than free agents, and the Doctor increasingly detaching from humanity. But here such inadequacies are presented with an ounce of caution and taken for what they are. This tastefulness also leads to an examination of what passes for normalcy and happiness among the companions of a time traveler. Do they ever get a happy ending? What is their reward? Is a mere human life good enough after you’ve seen the stars?