This new title is believed to be called 'Gotham City Imposters' after a retailer outed the project. Three new domain grabs by Warner seem to confirm everything.
BatmanHush.com, BatmanImposters.com, BatmanRedhoods.com, BatmanKnightfell.com, and BatmanHushgame.com are web domains that superannuation spotted around the time the online retailer blabbed about the new Batman title in the works.
The latest three - GothamRogues.com, TheGothamRogues.com and GothamCityImposters.com -that it'll be called 'Gotham City Imposters'. Batman: Arkham City is Warner's next big title in the franchise.