In my experience even politically engaged Americans don't tend to think about this question. Not that they'd disagree with probably representation, but they'll never bring it up before the specific policy issue du jour. Our parties have done an excellent job distracting us.
Just due to the nature of the American system, it would be virtually impossible to introduce on a national basis, so there's arguably no sense in spending time talking about it.
Many states also have deeply embedded 2 parties into their various laws and legal systems in different ways. A viable third, or fourth, or whatever party would have a LOT of friction to overcome to actually happen.
