OH My GOSH! (Spoilers for 3x12)

[The Evil Dead]

^
To me, Lost used to feel "jury-rigged" back in season 2, but since around mid-season 3 everything has seemed to gel together very well. It feels like the writers sat down, figured out the broad strokes of where they ultimately want to take the story and have been writing toward the series finale ever since.

We don't know what Christian Shepherd's connection to the island is or what the true nature of the Smoke Monster is but I just get this vibe from the show these days that the writers definitely know the answers to those questions.

 

[Starbreaker]

It's obvious they have spun their wheels in the past when the network probably wanted the show stretched out to 14 seasons.

 

[Mr Light]

The first season was nothing but stretching, and the second season as well to some degree. You'll notice that On-Island stories back then don't usually involve anything more than people sitting around talking or looking for food, whereas in S3 on it's more about exploration and action.