Assassin's Creed Valhalla is taking the franchise to the Viking Era, but it is also taking it out of the B.C. era. Many assumed that an ancient civilization would follow Origins' Egypt and Odyssey's Greece, but instead it's leaping 1000+ years into the future.
What this means is that the next Assassin's Creed game may be more open-ended as to which time period it explores, and while Assassin's Creed 2021 is by no means confirmed, Ubisoft's schedule means that there's likely one in the works. The franchise skipped 2016 to re-invent itself, so to speak, and skipped 2019. If this is a pattern, fans may expect a 2021 game with a 2022 skip year, but that poses the big question: what comes next? Most fans have a working wish list, and here's a few ideas on where the franchise would succeed.
Assassin's Creed Japan
With little doubt, one of the most demanded time periods and locations is Japan, particularly within the era of the Samurai or the last of the Samurai. It's history lends itself well to the Assassin-Templar struggle, and many jumped to Ghost of Tsushima as an honorary Assassin's Creed Japan title. Obviously, the two games would indeed share similarities, but Ghost of Tsushima is it's own thing. More Japan time periods in historic-fiction games is nothing to scoff at, though, and Assassin's Creed's remodeling of history in this time period would be an interesting thing to see.
Assassin's Creed: A Return to Rome
The franchise has a long history with Rome, Italy. Not only does Ezio's adventures take place in this area, but Amunet comes here after forming the Hidden Ones. Assassin's Creed Origins' DLC explores this and the foundation of the creed, but the history is so rich many would welcome another entry here. It's even been rumored before, but placing a new Assassin's Creed game during the rise of the Roman Empire would be interesting to see. Players could even continue to play as a wizened Amunet, which although this hasn't really happened since Ezio, many would see as good retribution for the mistreatment of Aya's character in Assassin's Creed Origins.
Assassin's Creed China
Recently, concept art leaked suggesting that Assassin's Creed could be going to China. It should be noted that the Viking Era entered the public discussion after concept art as well, although this is easily coincidental. Nonetheless, a core Assassin's Creed China game (not to be mixed up with the side-scrolling spin-off) could explore a variety of time periods and offer something unique for the franchise, regardless of where it went. Perhaps the most notable would be The Opium Wars, the Mongol Conquest, or the Three Kingdoms Era.
Assassin's Creed Mesopotamia
Although Assassin's Creed Valhalla is moving away from the ancient era, that doesn't mean future games won't revisit it. It would be interesting to see a return to this time period but set in Mesopotamia, otherwise known as the cradle of civilization. Mesopotamia offers Ubisoft the freedom of many other ancient civilizations, but depending on how far back it went, it could explain the origins of the Order of the Ancients/the Templars. There's also a vast number of periods to explore between 1000 BC and 1 AD, such as the assassination of Alexander the Great by Iltani, the Seleucid Empire, and far more.
Assassin's Creed Ireland
Assassin's Creed hasn't shied away from revolutions and wars of independence in the past, and while this may be unlikely due to the AC franchise's avoidance of more modern time periods, setting an game in the early 20th century of Ireland would be a good exception. In 1916, The Easter Uprising began a fight that, while immediately squashed after a week, would lead to a war of independence from 1919-1921. At least one Assassin in AC lore was involved with the event, but it could have easily been more. 1919-1921 was a guerrilla war, fresh off the heels of WWI, and so there would be a narrative reason for limiting certain modern weapon types and keeping the story focused on a new Irish Assassin.
Assassin's Creed Valhalla releases November 17, for PC, PS4, Stadia, and Xbox One, with PS5 and Xbox Series X versions to follow.