Hard to believe, with only four Lost hours left, that we don't really know what's going on this final season. Sure, there are some secrets they gotta save for the end--the biggest ones, in fact--but I never would have guessed we'd come this far without knowing what the altaworld is. And since we're going to be spending some time on the history of Jacob and the MIB, how much basic mystery that explains the plot can they hold back? I mean, they can't just explain this stuff at the end. Seems to me the altaworlders gotta figure out their situation and then do something about it.
There are two likely explanations. Since Desmond and others feel there's another world out there, one that's more "real," this one seems like a shadow world, Matrix-style. This is the future promised by the MIB? This is the world according to how things look when he's in charge, and everyone is controlled by him, maybe living, in essence, as brains in vats? I like this idea, since it would then require the Losties to get together and move beyond this world, smash it and go back to the real world, even if it may cost them. It fits a lot, but there does seem to be one obvious flaw: dead people are still living in this world. Locke, Charlie, Keamy, Charlotte, Dogen, Helen, etc. Why are they around? And note that Michael, whose spirit is stuck on the island, doesn't seem to be in the altaworld.
Which makes us turn to the other possibility, which has been offered to us in a pretty straightforward manner by the show. Sure enough, Jack's intervention in the incident made a change. It not only blew the Losties back to 2007, it also split the world and created what Faraday thought would happen. This fits with everything we see, including the shot of the island underwater, and Juliet seemingly flashing back and forth as she was near death. But what would this mean? Are both worlds equally real? How does the MIB figure into the altaworld? Is this a chance to defeat the MIB? But if it is, why does it seem less real, and the place you need to wake up from?
No matter what the altaworld is, there has to be a mix, or merging of the two timelines before the end, and it has to be an integral part of dealing with the overall situation.
Speaking of fixing the incident, I recently rewatched "The Variable," which takes place around the same time of the season where we're at now, and it reminded me of how strong the fifth season was. You may not have known everything, and characters may make foolish choices, but you knew it was real and they had serious choices to make.
"The Variable" is Faraday-centric, but the flashbacks can just as easily be seen as the tragedy of Eloise. The first time around, we see her pushing her son, but it's not till the end that we discover why--she's got to get him ready in time to go back to the island in 1977...and get shot...by her. So she's messing with her son's life just so she can have the honor of murdering him.
The show starts with Desmond, last shot by Ben during his attempt to kill Penny, rushed into the hospital. Eloise comes in and apologizes for her son getting Des in trouble. Faraday, via time/mind travel, had sent Des to her, where he met up with Ben. Actually, if I recall, it was questionable that Desmond's intervention was necessary. But that's how it goes on Lost, sometimes--what's important for the plot of one episode falls by the wayside the next.
Meanwhile, on the island in 1977, there's one great scene after another. The previous episode ended with the shocker that Faraday, after leaving three years ago, has returned on the sub. Miles shuttles him around on his mission. He talked about the constant before, but now he's interested in variables, and believes that maybe, whatever happened can unhappen. (Faraday spent his time in Ann Arbor. I so much wish the show had spent some time there. I know the place backwards and forwards and I'd love to see them try to make Hawaii look like it. Here's a hint--no palm trees, no mountains.)
He's on the island to talk to his mother, a younger (but not the teenage) Eloise. Time is of the essence, since the Incident is coming in a few hours, and he needs her help to change things.
He visits Chang (and we now understand the scene that opened the season--just as we later figure out Daniel's earlier flashback when he was crying at the plane crash) and tries to explain he's from the future, as is Miles (your son, btw). It doesn't work, but he believes it'll set things in motion.
Meanwhile, in Dharmaville, all hell is breaking loose. Sawyer has Phil--who knows too much--tied up in his closet and the Losties are trying to figure out their next move. They can't stick around so it's back to the Beach, or take the sub. (Juliet also sees the writing on the wall because of Kate.) But Dan (Sawyer calls him "Twitchy") comes in and explains his third way. This is the beginning of Jack finding his new purpose, and undoing the past. But before he and Kate and Daniel can break the sound barriers (Sawyer isn't thrilled, but Juliet figures why not), crazy Radzinksy comes on the scene and the shooting starts. Just in case you forgot, Dan reminds Jack this is their present, and they can still die. (Before this there's the touching scene with Young Charlotte--odd that Dan wants to change things, but does the very thing he knows he's supposed to do in the past.)
With time running out, Dan blunders into the Others' camp and holds Richard at gunpoint. This is kind of dumb--Locke did much better coming into camp holding nothing--but it can be excused, I suppose, because he doesn't have much time. As might be expected, standing in the middle of a bunch of Hostiles, he's shot. He looks up and sees who did it--his mom. All his life, she knew.
I don't think "The Variable" would make the top five of that short season, which is only an indication of how clear and exciting the plots were then. Here's hoping the final hours of the show have these kinds of thrills, and more.