Whoa... leave it to a student of dispensational theology to notice something like this.
The series is parenthetical to some degree. (In other words, it's like A - B - C - C - B - A.) Not exactly but roughly so. We've already noticed that the episodes in this season mirror the order of the episodes in the first season. Even the focus of each episode is the same. Kate-centric episode... a Locke one... then a Jack one... and next a Sun/Jin one... So, this season is mirroring the first season. But, guess what? It goes beyond that, but nobody noticed. Not only does Season 6 mirror Season 1... but Season 5 mirrored Season 2!
TWO: The survivors explored a lot of the various hatches and locations of Dharma. Several of the survivors are taken prisoner by the Others and stay with them for a while in one of the Dharma locations. They are gone from the survivors camp for nearly 3 weeks.
SIX: Some of the survivors went to the Dharma village, where they lived for 3 years among the Dharma people, going around to a lot of the Dharma hatches and locations.
TWO: And they also dealt with another group of survivors who crashed elsewhere on the island, a group which included a darkly cynical woman who is experienced with guns (Anna Lucia), a large husky brute of a guy who has a hidden softer side (Eko), and also a quiet and charming guy (Bernard).
SIX: We also met some more survivors from a crash on another part the island, including a darkly cynical woman who is experienced with guns (Ilana), a large husky brute of a guy who has a hidden softer side (Bram), and also a quiet and charming guy (Caesar).
TWO: Sawyer gets possession of all of the guns.
SIX: Sawyer is put in charge of the guns (he becomes the Dharma sheriff)
TWO: Ben (aka Henry Gale) is tortured by Sayid and held captive by Jack and other survivors, but one of the survivors betrays the rest by risking everything to rescue Ben, even though he knows Ben is the leader of the Others and is responsible for many terrible things
SIX: A young Ben is shot by Sayid. Jack and others refuse to help Ben, but another survivor takes it upon herself to risk everything to rescue young Ben, even knowing he will be the leader of the Others and will be responsible for many terrible things.
TWO: They found their way to the hatch. They argued over whether to do something (push the button) in the hatch. The season ended with a lot of arguing over whether to push the button, and finally they don't push the button, and BOOM!
SIX: They found their way to (what would be) the hatch, where they argued over whether to use some modern technology (bomb) to counteract the island's dangerous "energy." And then "pushed the button" and blew it up (or more accurately, it imploded, just like the hatch did in Season 2).
The series is very roughly parenthetical!
It is becoming increasingly apparent that this island takes to the extreme the concept of "history repeats itself." People who come here are cursed to repeat the same scenarios again and again. Sometimes, people come to the island and replace other individuals, taking over their roles in these ongoing and repeating dramas. Locke replaced Ben, Claire replaced Rousseau, etc. Some are theorizing that Kate will replace Richard (both arrived on the island in "chains") and that Sun will replace Dogen (both are Asian, love to keep secrets and are adept at herbal healing). As the adversary cynically pointed out, the same thing(s) happen every time. History repeats itself to the extreme on this island, on and on, with no end in sight.
And, no, I haven't even begun to investigate whether Season 4 mirrors Season 3. But certainly I see a lot of strong parallels between 6 & 1..... and 5 & 2. More on this later, as I investigate further.