According to Da Ginn of Rocksteady, the next installment in the Arkham franchise is going to take a bit more time than we all expected. Originally set for release on October 14, 2014, the game has now been delayed until the following year. From Ginn:
The very simple reason for doing this is to ensure we are delivering the awesome level of quality that Batman fans and gamers expect from this, the final episode and the epic conclusion to the Rocksteady Arkham trilogy. The Dark Knight will face his ultimate challenge in Batman: Arkham Knight now to be released in 2015.
Arkham Knight follows a growing trend of games that have been pushed back a year, such as Mad Max, The Division, and The Witcher 3. At least Bat-fans will keep busy in the new interim months, though, speculating the identity of the titular Arkham Knight and playing the recently-announced Lego Batman 3.