Pacing

Over the past couple seasons I'd say the pacing of Lost, as far as its overall arc is concerned, has picked up considerably.

There are a number of reasons. For one thing, you usually start a story a bit slower as you introduce the characters. Learning basic things about the castaways and the Island was pretty exciting in season one--you didn't need much more. But many complained about season two, which was probably faster paced that season one, because it didn't move ahead fast enough.

Since then three things happened which cut the slack. First was determining an end date. Until then, the show meandered a bit (showing tailies, not to mention Nikki and Paulo, who didn't amount to much). They figured rather than move the basic plot ahead, they could stop and deepen the characters with revelations in flashbacks. A little of this goes a long way. Look at someone as great as Sayid--he's had at least three separate flashbacks where we looked into what his "true character" is. With an endpoint, the producers knew what plot points they had to get through, and how much time they had to do it.

Second, and this practically saved the show, they started having flashforwards. Now we'd cut back and forth between two stories, but both were part of the arc.

Finally, they cut the number of episodes per season by a third. That guarantees they can't waste much time.

I'm not saying the first couple seasons were bad--in fact, I'm not sure if anything can compare to the first season in creating a sense of wonder. But when you look back, it's interesting to see them have whole subplots where next to nothing happens--Hurley creates a golf course, Sawyer hunts a frog, Locke builds a cradle, Hurley challenges Sawyer to ping pong. Those kind of plots have all but disappeared in the last two seasons, and, I expect, in the next one.