With Future SpaceSquid back where he belongs (he left clutching coffee filters and a child's drum, whilst muttering darkly about radioactive sea lions), we can talk about another Season Five finale in a more traditional way. This time, it's Supernatural under the microscope. Spoilers below.
"Swan Song" is a tough episode to judge, because it's very difficult to decide exactly what criteria I should be using. As an actual Supernatural episode, it was entirely acceptable. Hell, it was one of the better ones. It pulled together the overall theme of the show - the importance of family - very successfully, and made the most important point very well, namely that one's family is not simply who one is related to by blood. Sam and Dean's relationship is obviously key to everything, and John Winchester casts a long shadow over the proceedings as always (the similarities between the brother's responses to their father and Lucifer and Michael's responses to God are once again driven home effectively, if perhaps rather unnecessarily), but the Winchester boy's family is more than that. It's Bobby. It's Castiel. It's the Impala. In a weird way, it's even us to, as represented by Chuck. I was never very convinced by the idea of a "prophet" telling the Winchester's story as Supernatural novels, it all seemed a bit precious, but having him narrate the "final" story makes a great deal of thematic sense.
Given how well all of that hangs together (and having Sam regain his wits after seeing the toy soldier in the car door was particularly nice, though it might have been a lot nicer had we been given more warning), it would be churlish to point out how easily Lucifer is dispatched. At least, it would be were this an average episode.
It isn't. It's the zenith of five years of story, each season building on the last, and of an entire year's worth of "Fucking Hell, Lucifer will destroy everything ever and he can't be stopped". If you're going to stake an entire half decade's worth of stories (albeit partially retroactively) on a single confrontation, you quite simply have to make it worth it. Babylon 5 had the same problem with "Into The Fire" after only three and a half years, and BSG after five (depending on how you count it) with "Daybreak". Both of them failed, in very different ways (though I think "Into The Fire" is a bit under-rated). Supernatural failed, too. It might seem petty to complain about Lucifer's short shrift when the rest of the episode worked, but the fact that The Morningstar's shadow loomed so large over everything is not the viewers' fault, but the writers'. In its own way, this is the same problem suffered by the end of Lost; the show repeatedly told us certain aspects of it were desperately important, and then apparently changed its mind. I've lamented before the way Supernatural drifted from fun and scary mini horror films into a long-running family drama with ghosts, but I saw it as a necessary evil to prevent the show from getting stuck in a rut . If you're going to take this path, though, you need to have a much better picture of your endgame than this turned out to be.
Plus, as my esteemed flatmate pointed out, none of this is helped by Death showing up in the previous episode and being totally and unbelievably awesome. An episode of Sam and Dean trying to melvin Death? That I'd have liked to see.
 It also avoided to a great extent (though not entirely) the problem The X-Files quickly encountered, where each new "Monster of the Week" episode was either a paler retread of a previous concept (This guy can stretch his bones and eats livers! This guy can vomit acid and eats fatty tissue! This guy can fold himself in half and eats your pituitary glands!) or simply too bats-arse crazy to be taken seriously.