Den of Geek has a lengthy interview with Chris Perkins about the Forgotten Realms and The Sundering. He also very briefly touches on other settings, indicating that WotC hopes that other worlds will be covered in the future if the right story comes along. On past controversial changes to settings, he says "Our guiding principle is to embrace the past and not pass judgment or rewrite history. We’d rather let the fans tell us what they like about the Realms and focus on those elements going forward." (thanks to MerricB for the scoop!)