Just read through this thread, some thoughts.
Old Elizabeth became what Comstock wanted her to become and in 1984 she rains fire upon New York. (Curious as to why it took so long, considering it looked like Comstock was near ready to attack "sodom" already.) Ok so at this point in time as she watches New York burn, she brings Booker to 1984. Why would she do this? The only explanation to me is that the Lutece's at somepoint came to the conclusion that they needed her help to break the cycle repeating over and over. If they went to old Elizabeth (it would have to be after the destruction of sodom was inevitable). and showed her that Booker had tried over and over again to try and save her, but Songbird always stopped him, she could realise how huge a mistake she had made giving up hope.
In the Bioshock universe not every action has an equal and opposite reaction. Some actions never change (coin flip), some actions do change but have no real consequence (the necklace), some actions are cosmic anomolies where universes converge and then branch off from (the baptism). It may have taken the Lutece's a very long time just to figure out the branching out point, let alone trying to stop it.
Slate's fate becomes rather ironic when you look back, he sees DeWitt as a hero, Comstock as dictator. He wants DeWitt the hero to kill him, but either way it's the same man killing him.
How the hell did Comstock get rich? In his version he was a farmer, which is probably a lie, merely suiting the prophet narrative. Curious as to where his money came from and how he met Lutece.
Oh and if you take the end of credit scene as our Booker + Anna. Then by killing himself, Booker stopped himself becoming Comstock, thus stopping himself selling Anna to himself, thus never having to kill himself. Which is the exact same explanation to Red Dwarf series 7.
Whatever happened to the Wild West bounty hunter? The one hired to hunt Daisy? Last I remember hearing on the Voxophone, he began to sympathise for the kid he had wounded, and vowed to take down Comstock himself? Did I miss something, cause they were building him up to make an appearance.
Possible DLC side story?
I was curious about this as well. He goes from being a hired gun of Comstock to being a Vox sympathsizer (with an adopted Indian kid). He's a pretty nasty piece of work too, similar to Booker, who tries to find redemption.