I believe it was Neil Gaiman who suggested that writing serialized fiction is like jumping out of an airplane with a needle and thread and hoping you’ll have sewn a parachute before you hit the ground. Certainly there’s always been something of a slapdash, catch-as-catch-can, make-it-up-as-we-go-along feel to even the smartest and most ambitious of long-running television serials (Lost and Buffy the Vampire Slayer.)
This reckless approach lends TV series (and some comic book series) a thrilling, anything-can-happen sort of spontaneity, but it also exposes the seams at times. (Fans rightly dismissed Spike’s attempt to rape Buffy in Buffy the Vampire Slayer’s seventh season as a transparent bid by the show’s writers to remind the audience that Spike was evil, after having slowly neutered him over the course of three seasons.)
What I find most intriguing and satisfying about extended serial fiction is that it is uniquely equipped to reveal the startling extent to which a character can change over the course of time; while your average film might devote two hours to a given character’s narrative arc, Angel gave us five seasons to marvel at its title character as he struggled his way through 20-some episodes at a go. Removing commercials, each ostensibly hour-long entry offered perhaps 40 minutes of real story, but even then, you’re looking at a narrative which lasts well over 70 hours; a talented writer can do a lot with a character in 70 hours.