Well, as an American I hafta say, I think perhaps the Indian wars were the only time we were ever really the 'bad guy'. Sure, there have been a few instances here and there where we veered toward the darker end of gray, especially in Vietnam and Iraq, but even in those wars for the most part the people we've fought were at least as bad as us, if not worse.
It would be really hard at this point to make a game in which the Americans were the bad guys that didn't come across as preachy and ignorant of America's motivations. It's possible, and if somebody did it I'd totally play it, but I don't see it happening. Other than that, the only real options are the Indian wars or one of the grayer wars from the other point of view. I'd actually totally play that. Sadly that seems rather likely to be unpopular in America, which would certainly hurt sales, so again I'm going to have to say while I would enjoy it, it isn't likely to happen.
So yeah, I'd play the right game where my country is the bad guy, except that I don't see that game happening in the foreseeable future.