The release of Rocksteady's Batman: Arkham Knight has slipped into 2015. It was initially revealed the game would be out in October this year exclusively on the new consoles and PC.
From what has been revealed of the next entry in the Arkham series. Arkham Knight looks to be in scope a much bigger game. The city is about five times as big as the open world in Akham City. With the addition of being able to drive the Batmobile around Gothem. The game takes place after Batman: Arkham City. This time the Scarecrow threatens Gothem with his fear toxin causing the city to be evacuating leaving only the criminals. The game introduces The Arkham Knight, a villain created specifically for the game.
Rocksteady have seemed to try and distance themselves from the 2013 release, Batman: Arkham Origins developed by WB Montéal. Saying Arkham Knight will be the end of Rocksteady's Arkham trilogy. Seemingly ignoring that Origins even came out.
From what Rocksteady has shown the game looks to shaping up nicely and with it being made specifically for the new consoles it has a lot of potential to turn out great. Hopefully the delay will work out well for everybody and the time will be used to make sure the game is at its best for release.