1. Feudal Japan
A particularly rich period in history, with definable dynasties that could work as individual games in a series with a new protagonist at the centre, and more than enough political and military intrigue to make for some seriously entertaining. Obviously the opportunity to play as warring samurai, deposing shogun in order to establish a new dynasty, and fighting off uprisings intent on achieving the sam objective is an appealing one, and the idea of a lone wolf Samurai taking out enemies is a romantic one that would suit the gaming arena perfectly. The dynamic between warring families would be the perfect solution to the loss of the Templars/Assassins clash, and it would be an extremely attractive prospect to take control of a Samurai, with the obligatory weapons and the atmospherics of the era. But the most enticing story of all from Feudal Japan, and one of the most intriguing possible opportunities for Ubisoft and the Assassin's Creed is the persecution of the Japanese Christians who appeared after the Christian missions of 1549, and were persecuted in a full-scale destruction of the Christian community by the 1620s, that saw those who refused to reject Christianity killed, or driven underground. That would offer an interesting foundation for a future Assassin's Creed story, as well as a recognisable, and genuinely unlikable foe.