3. Paris during the French Revolution
Why it'd be awesome:
The tight, crowded streets of pre-Napoleonic Paris would be a perfect fit for the franchise's trademark parkour gameplay and provide a lot of opportunities for the virtual sightseeing, something that made Assassin's Creed II and Brotherhood a delight.
Why it could happen:
Like the Renaissance and the Crusades, the French Revolution is one of those historical events that's at the forefront of our cultural consciousness. We all know Marie Antoinette, Louis XVI, Robespierre. We all know the Storming of the Bastille and the guillotine. It's just the sort of era that Assassin's Creed loves to infuse with a new, conspiratorial subtext.
Why it might not:
While there was widespread violence and a decidedly fitting struggle between freedom and authoritarian control, the circumstances surrounding the events would make it hard to put together a rewarding narrative. No one wants to hunt down the big bad king using all their assassin skills just so they can sit around and watch a cutscene of his public execution by guillotine.