The more I think about this the less sense a camera that follows rails makes sense to me. Since we are already thinking about situations where the path may have to split in two (at which point the game isn't strictly linear), what is the necessity of the fixed camera?
Batman's use of the camera was restricted solely for the cinematic run sequence, not sure how well this would translate well into the full game's main form of camera, especially as the game involves solving a fair bit of puzzles.
Starting to think a camera that follows the player, that is user controlled (i.e camera follows the player's pivot, camera itself can be rotate (by say holding down the middle mouse and rotating/arrow keys).
Because it's hard to justify fixed camera angles other than for the sake of having it imo.
In conclusion, there is generally 2 kinds of 3rd person cameras, the behind the back one (think batman, asscreed etc...), and the follow and rotate camera (mmos, spectate cams in most games, etc...), not sure what we gain from straying to fixed methods.