Caring for historical accuracy in Ubisoft games is like caring for the taste of popcorn while watching a movie. Arguing over it is pointless, because neither accuracy nor taste were the point in the first place. Seriously, who fucking cares. Fetch quests, bland enviroment and health-spoonges enemies could be the really issue. Performance, bugs, that sort of stuff too, as usual. Odyssey had a giant loading screen for virtually everything and every time more than five NPCs appeared on the screen, the game went apeshit. This is the real problem.
Anyway, Assassin's Creed is such a huge franchise, they could place their next game anywhere they want - this is, like, the one and only opportunity to explore some of the more overlooked historical settings in a triple-A game. They could set it in ancient Persia, some of pre-columbian cultures, maybe ancient China, anywhere. And they chose Europe during medieval times, holy shit.
Also, they really need to stop with this whole "first civilization" nonsense, no one cares about it (and I hope no one ever did) and it actively hurts the whole experience. Assassin's Creed has always been about a particular style, not a specific story or event.