Cool. I love this francise.
My only concern is, as billiamb mentions, the climbing/vertical element. Europe is great because of all the great historial architecture to scale. The U.S. is still a relatively new nation during the revolution, and while I don't know much about historical structures, I doubt that there are many buildings as massive or impressive as what we've seen in Renaissance Italy.
I was hoping for French Revolution; King Loius, Three Musketeers, moustaches, pistols, smooth talking womanizing protagonist, epic cutting of chandelier cords and holding on to the other end effectively launcing you into the air and crushing enemies below you- that sort of thing.
I also wonder where the franchise is going. I haven't played Revelations yet, but the series so far is about hunting down certain cataclysmic items throughout history. If Desmond and gang are getting closer to modern times, where's the incentive to travel beyond the 19th century if we have their most recent locations?
Either way I'm excited. UBISOFT has great dev teams.