There are two well recognized methods of electing legislatures: single-member districts and proportional representation. Both provide something, of course, otherwise they wouldn’t be used, but they also both have shortcomings.
The single-member district (SMD) system (a.k.a. first-past-the-post) provides representation to each geographic area. But the winner-takes-all aspect forces us to have a two-party system, because if a third party runs a popular candidate, it will “steal” votes from the more similar of the other two candidates, running the risk that the less-similar one will win, despite a majority of support for the pair of similar candidates. For the voter, it’s strategically much better to stick with one of the two major parties, to maximize the chance that the candidate you agree with more will win. But since wins are usually close, a large minority of the population sees their choice left out of government. Instant-runoff voting would be an improvement, but it doesn’t change the fact that you’re giving out only one vote in the legislature.
Meanwhile, national proportional representation (NPR) guarantees that the overall national preference for each party is borne out in the election results. (Though I should note that single-member districts aren’t really all that bad here. Even with the huge variance in state populations, the total votes tend to closely match the number of senators elected from each party.) With so many seats to give out, a minor party has extremely good chances of getting someone in office and this leads to high voter confidence in casting a vote for a minor party, although some nations have rules to keep fringe parties from getting seats. But individuals don’t matter, and you can’t vote for them. If a party wins 50 seats, the top 50 people on its list are in. And to get as high as possible on that list, party members must toe the party line. This encourages conformity and group-think. In the extreme, you might as well not have individuals take seats, but just have the parties decide their platforms and cast their votes in blocs. Since individuals aren’t that important, it might feel like you’re voting on whether Coke or Pepsi is going to run the country. (Note of irony: I came up with that analogy before Citizens United v. FEC.)
NPR neglects the awareness of regional issues that SMD provides and the ability to choose a person rather than a party, while SMD neglects the ability of (nearly) every voter to have their choice actually get into power.
We could combine the benefits and eliminate the drawbacks of both by using proportional election on the district level, using individuals rather than parties—what I call the proportional-representation district (PRD). This would allow (nearly) every voter to have, in one person, both geographical and ideological representation. I have personally been in a situation where all seven people that ostensibly represented me—the President, both U.S. senators, U.S. representative, governor, state senator, and state representative—were of the wrong party. For three years, I couldn’t contact a Democrat, because I didn’t live in their districts, and the Republicans that should have been aware of my local issues thought the wrong way about them, so I didn’t have real representation. I'm sure many people, of all parties, have been in the same situation, and it's simply unfair and undemocratic.
(Part 2 is here.)