Heading into the final season premiere of Lost tonight, the big question at the back of every fan's mind is just how thoroughly the writers of the show have planned the series out. Will they answer all of the questions that need to be answered? (There's likely not enough space in 18 hours of television—plus commercials—to answer every question the show has ever raised.) Will those answers satisfy on some level? And, in the end, does it really matter if the show gives the many enjoyable characters it's cooked up over the years the kind of closure appropriate to their arcs? A significant portion of the Lost audience is probably only watching to see the final pieces placed into the jigsaw puzzle, and it seems unlikely they'll be pleased with what happens. But even more interesting is the significant portion of the audience watching to see if the show lines up as a planned-out narrative, if the series hangs together as one, big picture or if there are glaring contradictions and plot holes.
And to those people, I would say that if Lost had been painstakingly planned out from the first, it would be a much, much lesser show.
The continuing TV narrative is really unlike much else in the world of pop culture. The serialized novels of the 19th century and comic series removed from the obligations of big-company continuities come close to capturing the same sense of writers who have some idea where they're going while simultaneously making it up on the fly. But in both media, writers have absolute control over the characters and can make them do what they want. That's true to an extent on TV as well, but because TV is a collaborative medium, where directors and actors and technical personnel all have a say in the direction of the franchise as well, any carefully made plan will inevitably find itself warped and changed quite a bit.
As an example from Lost, I'd defy anyone to watch the first six or seven episodes of the series and predict that Josh Holloway's Sawyer was going to be anything other than an enjoyable rogue who would be killed off somewhere along the way. Instead, thanks to Holloway's charm and his chemistry with series star Evangeline Lilly (not to mention virtually every other female member of the cast), he's become one of the series' leads. On the other hand, the character of Charlie (Dominic Monaghan), set up as a character almost as important as Jack and Kate in the first few episodes, eventually exhausted his usefulness and became mostly interesting in the context of when and how the character would be killed off. Because the characters on Lost started out fairly thin—they mostly existed to serve the whims of the plot and/or rage against said whims—the actors and writers ended up wrapped in a collaborative relationship wherein the actors that defined their characters beyond simple types became more important to the writers' plans.
Could you plan out a TV show to the extent that some Lost fans seem to want the series to be planned out? As a matter of fact, you could, but it almost always ends up being a lesser series. Look, for example, at ABC's big Lost replacement hopeful FlashForward, now off the air until March in hopes that absence will make viewers' hearts grow fonder. The series' creators—David S. Goyer and Brannon Braga—entered the series with a hard and fast plan for where all of the plot points would lead and for where all of the characters would go. This was one of the things that made the show so attractive to networks, who'd been burned by serials that often seemed to have no idea where they were going before. In practice, though, it's been woefully terrible. The plot, confined by the fact that it knows exactly where it's going and what all of the characters are going to do, can't make any of the organic evolutions that any TV series needs to make to be successful. Everyone's trapped and hemmed in by a plan that has no wiggle room. (A similar thing happened to the vaunted '90s sci-fi series Babylon 5, though unplanned and uncontrollable events there forced enough of a sense of organic evolution onto that series that it had a little breathing room.)
In a recent interview with GQ magazine that mostly ends up revolving around what's going to happen in the final season of Lost, the show's showrunners, Damon Lindelof and Carlton Cuse, as well as its co-creator, J.J. Abrams, talk at length about how much of the show they've had figured out from the first. While much of Lost's overriding mythology was mostly in place from the earliest months of the show's existence, the writers freely admit that much of the character stuff was thought up on the fly. (Cuse and Lindelof make similar points and respond to an old David Fury interview claiming they were making the show up on the fly in this Maureen Ryan interview as well.) This irritates some fans—one of the biggest pieces of evidence for these fans is the fact that the producers brought on Michael Emerson without knowing exactly whom he would be playing when they did—but the writers offer a compelling defense for this method in the GQ piece: When you know what the backstory of your show is, you can drop in bits and pieces of the story when you need to press things forward. The game, then, becomes knowing which bits of information to drop when. (It also helps to have a genuinely complicated backstory, as Lost has.)
On the flip side, it's relatively easy for a show to have a largely ambiguous plan. When The Wire started up, its creators knew roughly what its seasons might take a look at, and they had an idea of how all of the characters might eventually fit together or morph into versions of each other, but their plan was amorphous enough to accommodate things like Dominic West's desire to ramp down his involvement in the show for a season or the popularity of other characters or other twists and turns in the production cycle. To be fair, every season of the show was intricately plotted out on a season level, but the overall plan had plenty of room for adjustment. Other serialized dramas may have vague ideas of where everything is heading but really only do heavy plotting on a season level. (See also: Mad Men, Breaking Bad, etc.) The single season seems to be the easiest way to come up with a coherent plot that hangs together, but science fiction drama fans demand more than that.
Serialized science fiction dramas seem wedded to their over-plots far more than, say, cop dramas. Indeed, it's almost necessary to have such a thing for any one of these shows, and when fans think the series didn't stick the landing (as too many have argued about the ending of Battlestar Galactica, a show I love but one that probably had too little of its plan thought out from the first), it leads to a sense that the series as a whole is not as good as it should have been. The best thing about these kinds of shows is often that anything can happen. To have a plan can often remove that sense of wonder and replaces it with a dutiful march toward a climax. When the Lost producers came up with their backstory but didn't bother to sketch out overall character stories beyond general thoughts, they probably made the one decision that kept the show fresh and interesting all these years.