I often see games getting delayed from their expected dates which honestly gives me hope. Some may see it as the development team slacking their efforts, but the more open minded would see the evident amount of extra dedication being implemented to the game.
I often become bored of annual releases, once a game is released year after year, the amount of innovation in the game decreases. If a developer has less stress on an actual release date, I view it as developers focusing on more of the quality of the game rather than rushing it to the deadline.
So Arkham Knight is to be released in 2015 on the Xbox One, Playstation 4 and PC. And honestly see this as a good thing, perhaps the games quality will increase to the standards which Asylum and City was at!