Rocksteady Studios game director Sefton Hill says that Catwoman was planned from very early on for Batman: Arkham City to be the complimentary character to Batman. However, the Robin discussion came up much later, and as far as future DLC announcements for the game, that will have to wait a while longer.
“The main thing we’re doing is the challenges for Robin and we’re doing some avatar skins as well . . . ” said Hill, and when asked about any story DLC, he smiled and responded, “I don’t think I’m allowed to talk about that at this stage.”