FWIW, I think that a two-party system is pretty similar in function to a parliamentary system. I used to think we needed more third-party representation (since my position aligns with one of those third parties), but I've changed my mind on that score. Not because I don't think the third party viewpoints are underrepresented (I do), but because the two-party US system functionally maps to the multi-party systems used elsewhere... once you take into account factions within a two-party structure and coalitions within a multi-party structure. What we call parties they call "coalitions", and what they call parties we call "factions".

On any given question with only two outcomes there will always be polarization, and if it's a political question the two sides will be roughly equal (because if they weren't the questions wouldn't be controversial and wouldn't become an issue in the first place). But the polarity of a single issue masks the underlying spectrum, or rather multiple underlying spectra, both orthogonal and interdependent. That doesn't mean the spectra aren't there, though.