User blog comment:TheBlueRogue/Bioshock Infinite DLC: Clash in the Clouds released, Burial at Sea announced/@comment-27.252.130.71-20130731115018/@comment-71.155.147.107-20130901184649

Irrational Games decided to return to Rapture for DLC rather than reuse Columbia as DLC because fan-demand was that strong in returning to Rapture, and that made IG decide to do that instead. Otherwise, IG would have just stuck to making Columbia DLC in the first place.

Return to Rapture's nostalgic success? IG made BioShock 1, and even 2k Marin's creative directors for BioShock 2, Jordan Thomas and Steve Gaynor, worked on Infinite, so I think that they wouldn't have that much of a issue of remaking Rapture, since they already had their idea of making Rapture in BioShock, and even if Thomas and Gaynor are not doing the DLC, they would have mentioned BS2 input with IG while they were working on Infinite if they had to go back to Rapture. I don't know what you mean by "nostalgic success", but the only thing nostalgic in the first two games were the music, clothing, furniture, and the Art Deco architecture. Everything else (Big Daddies, Security Cameras, flying bots, etc.) was mostly fan favorites, but they're not nostalgic. They're designed  with some aesthetics of that era's look, but they're only as nostalgic as old comic books, movies, and novels.

Also, Booker and Elizabeth (and her abilities) may be in Rapture before its civil war, but that doesn't necessarily mean they're literally going to be in every event mentioned in Audio Diaries, all because they're in that time of the event? More likely, IG would make levels that are new or ones based off levels they never got to add from the first game, and if there are some familiar locations, it may not be as much as a few. Most Audio Diaries in BioShock 2 didn't have every person go through these events in the same places as in BioShock. And even if there was anything new made in Rapture, it wouldn't be that different from stuff introduced in BioShock 2 that didn't happen or was shown in BioShock, such as an Atlantic Express line, EVE and Hack dart dispensers, BS2's Hack tool, or a Minerva's Den that has more variety of bots and inventions than what was shown in both games.