The latest Batman: Arkham game was not developed by series creator Rocksteady. But, of course the studio is working on something. And whatever it is, it's coming in 2014.
Internet supersleuth Superannuation discovered several job postings matching text of Rockstead's career openings for what is "tipped to be one of the most successful games of 2014." If all goes according to plan, it looks like Rocksteady's next will be ready next year.
It's likely Rocksteady is working on a proper sequel to Arkham City. As clearly labeled by the title, the recently-released Origins was a prequel. Kevin Controy, the de-facto voice of Batman said he was working on an Arkham game--but he doesn't appear in Origins.
Rocksteady teased "Arkham World" at the VGAs, which many viewed as a prank pulled by the Joker. However, Warner Bros did also register the "Arkham Universe" domain name, suggesting many more games to come in the Arkham franchise. With two developers working on the franchise on alternating years, it appears Warner Bros is well on their way to annualizing the franchise.