8. World War I/II
The writing team may have already rubbished talk of the Second World War as the worst possible historical period for Assassin's Creed, but that doesn't mean a 20th century world war couldn't work well as the setting for a future title. We aren't talking a Call of Duty-style open-environment shooter, by any means, as the trenches of WWI or WWII, and the occupied lands of Europe could offer bountiful gameplay opportunities for the hooded assassin. Provided Ubisoft ignored the easiest route of making a more conventional shooter - which you would have confidence they would manage - and stuck rigidly to the stealth and close combat manifesto of the franchise, there is no reason a more modern warfare setting would work. Imagine the opportunity to attack German high-command headquarters, and take out high-profile targets in one sequence, and then being charged with joining an attack on a stronghold position across open terrain, using your stealth skills to avoid contact with the enemy, creeping through trenches to wipe out unknowing enemies as a sort of special team edition to the rest of the army in order to achieve your own objectives. Those grand combat sequences would have to be sparingly used, in order for the accusations of CODifying to be kept to a minimum, but I would suggest that any attempt to downright reject the historical period because of the way other genres have presented it is a destructively limiting stand-point.