There's another installment of Inside Assassin's Creed III ready for you. Connor is the assassin in this game and this episode explains the role he'll play in the American Revolution and the characters you'll encounter.
The trick here is Ubisoft wants players to feel like a part of history, where you're witnessing, interacting and influencing the outcome of events that actually happened. With such well known stories like this, you can only alter so much with your decisions and action while still keeping the established story intact. EA's Godfather games a few years back did an underrated job of having your original main character interact with iconic people and scenes from the Godfather movies without ruining the continuity and flow we all know while still putting you into iconic scenes.
How Assassin's Creed III pulls the same trick will be very telling because there's a lot to do in this one and a lot of people/places to see.