I find that to be part of the problem, though. By systematically lumping all of the possible different parties into two parties, individual politicians are pushed to either toe the mainstream party line or become pariahs. The choice for which direction a party goes becomes linear ("A more moderate or more conservative Republican Party?"). Each voter is left with one of two choices, with no chance that their vote will affect policy if they disagree with both choices. And those who are poor fits to the center of either major party end up with few who meaningfully speak for them in government. It causes apathy and disenfranchisement. I don't think the viewpoints I hold are too unusual in the context of American politics, and yet, who can I look to as somebody I agree with in power? I guess I admire Justin Amash, and maybe the Paul family in a stretch (just don't make me defend everything they do!). I'm really grasping at straws here.
All that changes under a proportional representation scheme, though. I personally like the Dutch scheme best, but I suppose that something like the German scheme would fit better with the American mentality. Either way, I think we'd immediately see an alleviation to all the problems I mentioned earlier. We'd probably end up with a half dozen important parties, with shifting coalitions, and with the Democrats and Republicans still dominant (at first), but not a duopoly.
My guess is the party scheme would look like this:
Republicans: Right-leaning, social conservative, hawkish
Democrats: Left-leaning, social liberal/moderate, moderate foreign policy
Party 3: Right-leaning, social liberal, dovish (Libertarian Party or Reform Party?)
Party 4: Left-wing, social liberal, dovish (Green Party?)
Party 5: Right-wing, Paleoconservative (Constitution Party?)
Party 6: Left-leaning, social conservative, hawkish (some kind of populist party that seems very conservative but supports quasi-socialism, an "old people party" of sorts... I think there's an opening here)
The Germans end up with something like this... CDA is sort of like the Republicans in that scheme (less conservative maybe, but then the whole German paradigm is shifted from the American one); SPD is sort of like the Democrats; FDP is like Party 3; Greens and/or Left are like Party 4; and NPD somewhat bridges Party 5 and Party 6.
In the Netherlands, CDA is like the Republicans (bearing in mind a similar paradigm shift from America as in Germany); PvdA is like the Democrats; VVD is like Party 3; SP and/or GL are like Party 4; and PVV, CU, and SGP are different approximations of Party 5 and Party 6.
I could go on, but I'm having too much fun with this, and diverging from my point. Which is that the European proportional representation model is better.