I rewatched this recently and feel it is one of the most thought-provoking episodes in the series. This was the episode where "Oldo" slaughtered 8,000+ people just to make sure young Odo and Kira had a chance to go out on their first date together. But before that happened, other issues and questions were raised, such as:
1. How was Worf so sure what would happen if they didn't repeat the accident? He had only just arrived on the planet and said it like it was a matter of undeniable fact that their timeline would simply cease to exist, there wasn't a doubt in his mind. But why, did he watch the episode beforehand?
2. Why was Jadzia so upset after she realized Yedrin lied about the duplication plan? Is it really that shocking? He's trying to preserve the existences of 8,000 current lives plus all the people that lived and died before the current 8,000. She was sooo mad at Yedrin, giving him a "how dare you!!" face straight out of O'Brien's worst Keiko nightmares. It was such a childish reaction.
3. Yedrin made a good point, that in the first or original run of the timeline, they all crashed and got stranded by "fate" or chance alone, and in that sense IS what was meant to happen, and the second run of the timeline (which is what we are watching in this episode), the second Defiant is given foreknowledge that the first run Defiant never had. The honourable thing for the second Defiant to do, IMO, is to repeat the accident. BUT the premise is flawed regardless as the second run Defiant crew has foreknowledge of things the first run Defiant never had, which should result in changes in events and different descendants. UNLESS Yedrin somehow made a painstakingly detailed record of who, where and when people hooked up and the second run Defiant crew pretty much repeats everything exactly the same following this script? The first timeline's history was doomed to be contaminated the moment they began interacting with the second timeline's Defiant. What Yedrin's plan SHOULD have been was to somehow mask the colonies and life signs in some way so that they weren't detected from orbit. Then the second Defiant would have done the exact same things and history would have repeated itself without all the drama.
4. Sisko said he didn't have the right to ask Kira to sacrifice her life to save 8,000 lives, or even 8 million lives. Really though? Captains do more than simply ask, they ORDER people to their deaths all the time to save lives. It seems to me the least he can do is ASK Kira if she was willing, never mind ordering her. Sisko was being such a chump in this scene.
5. Kira is immediately willing to die to save 8,000, thanks to her faith (presumably not fearing death because she believes she will be with the Prophets?). But has it ever been established that Bajorans have an afterlife? I understand Bajorans came to worship the Prophets thanks to being sent magical orbs and such in their history, but why are they so confident they will live on with the Prophets when they die? Is it written in their sacred texts? Has any character ever had an afterlife experience?
6. Miles says he doesn't believe in her Prophets, but why? It's not like other religions with no evidence of a God being real, the Prophets are as freakin' real as can be and proven to be godlike in their nature. Does he think Sisko has been making up all his own experiences with these beings? Miles also said no one had the right to tell him he couldn't go home to be back with his family. He's in Starfleet, his superiors have the right. Plus this was his big chance to finally escape Keiko, I would have expected him to be the FIRST to jump aboard the Gaia bandwagon, not the last.
7. Oldo trying to manipulate Kira into changing her mind about not going home to get treatment to live on was so scummy. Kira said she couldn't let 8,000 people die, then Oldo played the card "what about all the people who will never be born if the Defiant never returns to the station", and Kira correctly rebutted that those people don't exist yet, these people do. Oldo doesn't give ONE SHIT about other people's lives, all he cares about is his younger self getting a shot with Kira. What a douche. On a related note, I'm not sure if they ever made it clear why they simply couldn't let Kira take a shuttle and go home to the station alone. (Not a perfect solution as it is still a change to the original events that should have some repercussions on the original timeline and descendants, unless again Yedrin provided them a script to follow.)
8. After it is revealed what Oldo did, Kira was dismayed, and yet she still hooked up with Odo later on? Was she secretly flattered or turned on by Oldo's total devotion to and/or infatuation with her? It seems to me Oldo wouldn't have cared if there were 8 BILLION descendants that would've gone "poof", all that mattered was Kira, or perhaps more accurately giving his younger self a potential shot with her. This is the definition of Playing God, the same way the Founders do. Is this part of the attraction for Kira? She's in love with her gods the Prophets, and Odo is a godlike being in his own right. Kira's got a thing for gods it seems in all their shapes and forms.
9. Did Odo and Kira keep Oldo's actions a secret from everyone else? If not, how could anyone ever feel they could really trust Odo after this? Granted this was an older version of himself with different experiences underpinning his actions, but it still shows that if push came to shove he'd be willing to betray anything and everyone to serve his own selfish desires; he would hand the entire Alpha Quadrant to the Dominion on a silver platter if it meant saving Kira's life -- AS LONG AS SHE WASN'T DATING SOMEONE ELSE, that is.
10. In the second to last scene, Sisko left us with a platitude after the colony vanished, that being: "They existed, and as long as we remember them, they always will." And that's that I suppose? (He might as well have just said "No big deal, let's go home people....hey I know what will cheer us up! Baseball!") Jadzia seemed more than satisfied with this platitude, she had a look of serene comfort and acceptance upon her face after this simple remark. Somehow all these people never lost a wink of sleep after this experience for the rest of their natural lives. Just like that Tuvix episode of Voyager. (If Tuvix had the chance to be buried he'd be rolling over in his grave right now.)
1. How was Worf so sure what would happen if they didn't repeat the accident? He had only just arrived on the planet and said it like it was a matter of undeniable fact that their timeline would simply cease to exist, there wasn't a doubt in his mind. But why, did he watch the episode beforehand?

2. Why was Jadzia so upset after she realized Yedrin lied about the duplication plan? Is it really that shocking? He's trying to preserve the existences of 8,000 current lives plus all the people that lived and died before the current 8,000. She was sooo mad at Yedrin, giving him a "how dare you!!" face straight out of O'Brien's worst Keiko nightmares. It was such a childish reaction.
3. Yedrin made a good point, that in the first or original run of the timeline, they all crashed and got stranded by "fate" or chance alone, and in that sense IS what was meant to happen, and the second run of the timeline (which is what we are watching in this episode), the second Defiant is given foreknowledge that the first run Defiant never had. The honourable thing for the second Defiant to do, IMO, is to repeat the accident. BUT the premise is flawed regardless as the second run Defiant crew has foreknowledge of things the first run Defiant never had, which should result in changes in events and different descendants. UNLESS Yedrin somehow made a painstakingly detailed record of who, where and when people hooked up and the second run Defiant crew pretty much repeats everything exactly the same following this script? The first timeline's history was doomed to be contaminated the moment they began interacting with the second timeline's Defiant. What Yedrin's plan SHOULD have been was to somehow mask the colonies and life signs in some way so that they weren't detected from orbit. Then the second Defiant would have done the exact same things and history would have repeated itself without all the drama.
4. Sisko said he didn't have the right to ask Kira to sacrifice her life to save 8,000 lives, or even 8 million lives. Really though? Captains do more than simply ask, they ORDER people to their deaths all the time to save lives. It seems to me the least he can do is ASK Kira if she was willing, never mind ordering her. Sisko was being such a chump in this scene.
5. Kira is immediately willing to die to save 8,000, thanks to her faith (presumably not fearing death because she believes she will be with the Prophets?). But has it ever been established that Bajorans have an afterlife? I understand Bajorans came to worship the Prophets thanks to being sent magical orbs and such in their history, but why are they so confident they will live on with the Prophets when they die? Is it written in their sacred texts? Has any character ever had an afterlife experience?
6. Miles says he doesn't believe in her Prophets, but why? It's not like other religions with no evidence of a God being real, the Prophets are as freakin' real as can be and proven to be godlike in their nature. Does he think Sisko has been making up all his own experiences with these beings? Miles also said no one had the right to tell him he couldn't go home to be back with his family. He's in Starfleet, his superiors have the right. Plus this was his big chance to finally escape Keiko, I would have expected him to be the FIRST to jump aboard the Gaia bandwagon, not the last.

7. Oldo trying to manipulate Kira into changing her mind about not going home to get treatment to live on was so scummy. Kira said she couldn't let 8,000 people die, then Oldo played the card "what about all the people who will never be born if the Defiant never returns to the station", and Kira correctly rebutted that those people don't exist yet, these people do. Oldo doesn't give ONE SHIT about other people's lives, all he cares about is his younger self getting a shot with Kira. What a douche. On a related note, I'm not sure if they ever made it clear why they simply couldn't let Kira take a shuttle and go home to the station alone. (Not a perfect solution as it is still a change to the original events that should have some repercussions on the original timeline and descendants, unless again Yedrin provided them a script to follow.)
8. After it is revealed what Oldo did, Kira was dismayed, and yet she still hooked up with Odo later on? Was she secretly flattered or turned on by Oldo's total devotion to and/or infatuation with her? It seems to me Oldo wouldn't have cared if there were 8 BILLION descendants that would've gone "poof", all that mattered was Kira, or perhaps more accurately giving his younger self a potential shot with her. This is the definition of Playing God, the same way the Founders do. Is this part of the attraction for Kira? She's in love with her gods the Prophets, and Odo is a godlike being in his own right. Kira's got a thing for gods it seems in all their shapes and forms.
9. Did Odo and Kira keep Oldo's actions a secret from everyone else? If not, how could anyone ever feel they could really trust Odo after this? Granted this was an older version of himself with different experiences underpinning his actions, but it still shows that if push came to shove he'd be willing to betray anything and everyone to serve his own selfish desires; he would hand the entire Alpha Quadrant to the Dominion on a silver platter if it meant saving Kira's life -- AS LONG AS SHE WASN'T DATING SOMEONE ELSE, that is.

10. In the second to last scene, Sisko left us with a platitude after the colony vanished, that being: "They existed, and as long as we remember them, they always will." And that's that I suppose? (He might as well have just said "No big deal, let's go home people....hey I know what will cheer us up! Baseball!") Jadzia seemed more than satisfied with this platitude, she had a look of serene comfort and acceptance upon her face after this simple remark. Somehow all these people never lost a wink of sleep after this experience for the rest of their natural lives. Just like that Tuvix episode of Voyager. (If Tuvix had the chance to be buried he'd be rolling over in his grave right now.)