Canada still pays respects to the monarchy - I don't see it being an impossible scenario. The revolutionaries won because they broke the rules of war of the time, were fighting for something they believed in, had help from the French, and got lucky a lot of the time.
What if it were different, though? What if the British had been more lax with their taxes and policies? What if they had granted Americans a large degree of freedom, especially representation in parliament? Then a rebellion would have seemed silly and pointless. The rebels wouldn't have received quite so many to fill their ranks, and would have been regarded by the majority as trouble makers and destroyers of the peace.
Meanwhile, the clear-minded and somewhat upset (Just not to the point of open rebellion) writers of the Constitution would have done all their famous tidbits in secret, preparing the country for the day when a democracy could be established in America.
You already have three factions - The British, the Rebels, and the Democratic Revolutionaries. The Rebels and Revolutionaries might join together, but their different ideologies, especially concerning terrorist tactics, could rupture the alliance easily.
In a game setting, it comes down to the ends justifying the means - Do you choose the route of hitting them where it hurts and tearing them apart from home? Or do you join the idealists, fighting bravely in heated combat and only striking military and tactical targets?
Sorry, I'll quit hijacking the thread. Back to Home Front.
I guess the determining factor for me will be the multi-player. If that's good enough, then it doesn't even matter if it has a single-player campaign or not.