If they can maintain the Bioshock atmosphere with "amazing, impossible, beautiful but horrifying" setting instead of specifically underwater, then yeah, I think this could do Bioshock proud. There are a lot of issues with this, of course, and they scare me. yeah the floating place is gorgeous, but how can it possibly be as terrifying as Rapture was?
It's definitely a ballsy move and I'm sure it'll be a good game. Whether or not it's really Bioshock in its heart will depend on the gameplay and whether it can stab you in the guts with terror or not.