I'm honestly O.K. with the American Revolution thing. I mean, Desmond is kind of...American. We'd have to go to the country at some point. From both a gameplay and literary standpoint, the American Revolution makes sense. Is it the most interesting? Of course not. Is ok? Sure.
I mean, throwing in the assassin-y backstory with country's civil war is more difficult than a war between a rebelling colonel and a then-world power, especially considering the fact that explaining templar influence is easier here than say, the American Civil War. That is not to say that the templars didn't obviously spread their interest to the new North American state at some point, though.
Also, the same AC feel would be lost amidst the (more) technologically advanced wars of the 20th century (Crimean, WWI + II, Mexican Revolution, etc.). Setting the game in this point allows you to maintain the same feel because guns were still not greatest in the 18th century, although they'd be admittedly better than the gun(s) found in AC:Brotherhood and Revelations.
In conclusion, while the American Revolutionary War may not be the coolest new setting for the game, it should prove to be enjoyable, especially when you throw a tomahawk into the mix with hidden blades, poisons and bullets. I'm looking forward to this game, considering Ubisoft hasn't greatly disappointed me, yet (although the AC:R character designs were kind of...meh). I just hope they don't extend the new ancestor's story out like they did Ezio, or at least make him a good enough character if they do. I'm still looking forward to epic underground temple alien-futuristic parkour in Assassin's Creed: Desmond's Story.
Now if you'll excuse me, I need to actually start playing Assassin's Creed Brotherhood so as to play catch up...