You can't really have direct democracy, specially not in a country with millions of people. I'm from Switzerland and we have probably the most direct democracy

You can't really have direct democracy, specially not in a country with millions of people. I'm from Switzerland and we have probably the most direct democracy in the world and we do have parties (many in fact) and representatives. The direct democracy aspect however is a very important check on what the government does and it allows for grass root initiatives to get national discussion. We are not part of the EU because of population went against the parliament on that issue. Something most other countries in Europe didn't get the option to do. It also has some negative sides as well. In general I would say having more parties, would help a lot. If your social circle is full of people who have slightly different parties switching party is a lot easier. In the US the most important system is the get away from First Past the Post single election for congress and presidency. Remove primaries, use either larger districts with representative representation of some kind, or smaller districts with ranged/score/star voting. Ban the president primary and have people use range/score/star voting to select an actually popular president. This I think would eventually destroy the two party system in the US.