Songbird will probably be solved via DLC, but he is forever lost in the main game. The vigors just exist, ok. But, why am I the only one using them. at all? See, they are everywhere in the city, and you will find the Crow/Coffin/Sword/KKK guy, or the Armor on Fire guy, but that's it. Why the other enemies do not use vigors, but, if you played Industrial Revolution they say the police is using at leas Bulking Bronco, probably charge too, since you find in the armory of a police station.
And if you follow the many, many speeches of the Lutece fellows, you will see they say that something is and always will be. So, kill Booker is 100% useless. And even worse, every time they kill a version, it will mess up the memories of the other versions, so, maybe that explains the post-credits scene. So yeah, again, the ending just do not work. And a last thing, since she killed Songbird and Booker, and said she would kill Comstock, and yet, was surprised when you do it, I have to say that Elisabeth is, maybe, a bit more dangerous and out of control that she looks. Years locked away in that tower might be the case.
The tower is another absurd: Why Comstock would hide her even from himself? Why hide Columbia from her? If she lived with him from the start, even inside that tower, you can bet that Booker would not be capable to take her away.
And the thing about killing the Lutece and Lady Comstock, first, if he liked her, why not tell her how he got the child? Maybe he killed her more for the effect over the public than anything else. The Lutece crew could see the future! Kind of. I do believe the lady Lutece would be curious about future, their future. Maybe she was, and maybe she desired that. And by the way, I would love if Irrational had called Mark Meer to be the male Lutece. It would just be nice.
About the philosophies involved, well, I would love to be capable to understand and build a good argument, but, it's just
not my area. Anyway, yeah, it's a bit weird to see the whole prejudice theme just disappear in thin air after the first scene. Bioshock Infinite world have depth, but it's hide in well guarded recorder devices, not in the story we live through.
But really, it's one of the best things I ever experimented in gaming.
PS.: At the ending, imagine if after she visited Rapture, she also could take him to see the stars even a bit more closer, maybe, in the UNN Rickenbacker...