Assassin's Creed: Odyssey - 9 Future Settings Ubisoft Must Use
1. Mayan America
More concept art that works https://goo.gl/images/QRzz8W
Archaeology suggests there used to be huge cities in the Amazon rainforest - they're gone now, but hint to past huge societies in a region people always assume is a wilderness. Setting a game here would let Ubisoft use their artistic license to make a world they envision.
Throughout the series there seem to be hints to Mayan legends - from the 2012 Apocalypse, which was real in the game, being predicted by them, to ruins throughout Assassin's Creed: Black Flag using architecture very similar to Mayan pyramids and ziggurats.
As an alternative to New York being the game to wrap up the lore, setting a game in Mesoamerica could be an interesting way to get to the bottom of some long-standing questions and plot holes. Ubisoft have done enough world-building at this point, but they need to help us make sense of some of it.
Assassin's Creed Odyssey seems far more focused on the culture and history of the period than the assassination-related plots and skullduggery that most games were focused around, so trying to predict future games can be hard when Ubisoft keeps changing the core of the games. However, these locations would all make for fascinating and varied games.