
I'm a little surprised this episode isn't entitled 3:16, since that's roughly the amount of time spent on the island. I'd take it a step further and say "time spent doing anything interesting" but Damon and Carlton take enough abuse as it is.
Right off the bat I want to say that I really enjoy LOST's spiritual themes, whether it's old-school religion or more generalized concepts of faith. So when I say that I can't stand this episode, I don't want people getting the impression that it has anything to do with scriptural references or time spent in a church. Nothing could be further from the truth.
No, what I can't stand about this episode is that it starts off with a full ten minutes of painfully acted exposition in one room, then moves to a smaller room with several MORE minutes of painful exposition. Then it moves back out to the nave of the church where Ben busts out a speech about Thomas the Apostle.
You know it's bad when a scene in a retirement home actually speeds things up. That's where Jack conveniently gets one of the items he needs to re-create the Oceanic 815 conditions, as directed by Eloise Hawking.
The Oceanic Six (minus Aaron) end up on Ajira 316, as does Ben Linus and John Locke in a coffin. How Sayid and Hurley ended up on the flight wouldn't be revealed until later in the season. Ben and Jack sit next to each other, trading a few signature lines back and forth before severe turbulence ensues. They're caught in a time flash, voila, Jack, Kate, and Hurley are back on the island.
As for the episode theme, well, it seems Damon and Carlton were trying to draw a parallel between Jack learning to believe in Locke's beliefs and the biblical account of Jesus.
John 3:16 says, "For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life."
The common ground between Jesus and Locke: both sacrificed themselves with the hope that people would one day come to believe.
Ben's story about Thomas the Apostle is as follows:
BEN: When Jesus wanted to return to Judea, knowing that he would probably be murdered there, Thomas said to the others, "Let us also go, that we might die with him." But Thomas was not remembered for this bravery. His claim to fame came later, when he refused to acknowledge the resurrection. He just couldn't wrap his mind around it. The story goes that he needed to touch Jesus' wounds to be convinced.
JACK: So was he?
BEN: Of course he was. We're all convinced sooner or later, Jack.
And so the interesting part (perhaps the only one) occurs when Jack speaks to Kate on the Ajira flight:
JACK: It's pretty crazy, huh?
KATE: Which part?
JACK: Hurley, Sayid... being... on the same plane. How did they end up here?
KATE: They bought a ticket.
JACK: You don't think that it means something? That somehow... we're all back together?
This is the first sign of Jack in transition, a man looking beyond the empirical realm for answers. The old Jack wouldn't have suggested anything "means something." Hurley's numbers were just numbers. The button in the Hatch was just a button. Et cetera. Maybe Ben was right — it was only a matter of time before Jack believed what Locke had been saying about the island all along.
Whether I'm spot-on or way off in this analysis doesn't matter much to me, though. As much as I love themes and parallels it's never a reason to make an episode this slow and bizarre. I have an incredible amount of respect and admiration for both Damon and Carlton, which is why I'm amazed they allowed close to 15 full minutes of pure exposition. They almost always opt to naturally present complex information through the story itself. Using their own words, they prefer to "present a crisis" in lieu of exposition, much like they did in the Constant to avoid long diatribes about time travel.
Having the Losties stand around classroom-style in the Lamp Post, asking Eloise questions and even filling in blanks on occasion, was not LOST. Not even close.

This will sound overly harsh but I wouldn't say it if I didn't feel it were true: the exposition scene with Fionnula Flanagan (Eloise) is the worst 10-15 minute stretch of acting in the entire series. I remember thinking the first time around, "Is this a dream?" ... Eloise's over-the-top delivery was just that ridiculous.
I'll be even more specific with the worst few lines in the series, which were delivered after Sun gave Eloise an apple and excitedly answered her quiz question correctly.
ELOISE: Yes. The island. [pause for no reason] They'd gathered proof that it existed. They knew it was out there somewhere, but they just couldn't find it. Then a very clever fellow built this pendulum on the theoretical notion that they should stop looking for where the island was supposed to be [pause] and start looking for where it was [dramatic pause] GOING [pause] to be.
Blech. Just when I thought the torture of the Lamp Post exposition was over, Eloise simply pulled Jack into a smaller room for even more exposition. Matthew Fox did his best to make it dramatic by yelling "THIS IS RIDICULOUS!" at one point, but sorry Matt, not even you can save this one.
Michael Emerson got just about every memorable line in 316, most of them delivered while he was on the Ajira plane.
Bonus points to Raymond J. Barry for portraying Jack's grandfather Ray. A little bit of comic relief was desperately needed. More bonus points to Kavita Patil, the Ajira flight attendant, just for existing. She was very nice to look at after I'd become completely disenchanted with the episode.

Other than the impressive dive/stunt at the waterfall pool, the visually appealing design of the Lamp Post station, and the turbulence effects on Ajira 316, there was really nothing going on here. This would've been the perfect episode to assign to Stephen Semel since he was clearly trying to bolster his fledgling directorial career.
Please note that this score is not a reflection on Stephen Williams, who is a fine director. It's just that there was hardly anything visually compelling about 316 at all, which is no fault of his own.

There's a Season 4 episode called "The Other Woman" that I used to strongly dislike, but once I really thought about the chess game being played between Ben and Widmore I came around to finding it tolerable.
316 will have no such luck. No amount of thought will make Flanagan's acting anything less than abysmal. No amount of thought will change the fact that everybody and their grandmother knew the O6 would end up back on the island — the beginning of 316 even removed all suspense and showed it to us in the opening act.
In short, unless I'm rewatching LOST with a pure newbie in the future you can bet I'll be skipping this one.

If "bizarre" counts as atmosphere then 316 did a bang-up job. Even setting aside the Lamp Post scenes, very little seemed to fit in this episode. Even some of the smaller details, like Locke's coffin sitting just a few feet away from huge slabs of meat, were incredibly lame whether they were attempts at symbolism or simply arbitrary decisions.
I love character development as much as the next guy, but the beauty of LOST is that we often learn so much about our characters based on their reactions to circumstances. In this case they were merely buckets standing by and waiting for information to be poured in.