The setting for the next Assassin's Creed may have already been decided. Chaverot Bertrand, director of Ubisoft Brazil, says that the game will be taking place in his country.
Bertrand revealed this bit of information to Techtudo (via GameStop). He didn't mention whether this would be the central setting, though. In Assassin's Creed 3, Desmond traveled to the country but only for a single mission.
Brazil would certainly be an interesting backdrop for an AC game, regardless of time period. It's not a country commonly seen in games so there's a lot of untapped material.AC3 placed new emphasis on wilderness exploration and Brazil's rainforests would be more than adequate for that sort of gameplay.
It seems likely that the next Assassin's Creed will continue the story of Connor, the Native American hero introduced in this fall's Assassin's Creed 3. I'd expect Ubisoft to do something like they did with Assassin's Creed 2: release sequels with the same protagonist on an annual basis. I'm not really sure why Connor would go to Brazil but again, that country might not be the main setting.
Even if Ubisoft plans to release a new Assassin's Creed next fall, they probably wouldn't want to reveal the game's setting this early in the game. I'd expect some backpedaling once Ubisoft's PR folks return to the office on Monday. We'll be told this was all a misunderstanding or a mistranslation or whatever.
