One thing not mentioned in this article that could be interesting is multi member districts. Instead of reducing the size of a district to 1 per 40,000, you could easily make the district 120,000 and have 3 representatives from it. This is actually a more reliable way to bring in third parties, because rank ordered voting could be used to determine the three winners. There are a lot of places where you might get three from a single party or two and one, but there are also a lot of places where there would certainly be Greens or Libertarians who have enough support to come in second or third. I despise the GOP, but I'm not naive enough to think that anywhere in the world is better served by a single point of view. It's hard to imagine bringing in more voices with less power per voice could be a bad thing for the country. We're already getting full blown internet conspiracy theorists in Congress, so it's not like it can get any worse.
Duverger's Law holds that plurality elections will give you two parties. Washington uses a top-two primary system which means our insurance commissioner, who has held the office since 2001, is running against this guy. (He's 36) Note that the dude who channels the ghost of Nixon won a slot in the top two because he's Republican. The Libertarian guy was actually more qualified but I mean... he's a Libertarian.
There were a couple of these in our election this year, but this entry definitely won the Weirdo Award. I can't even comprehend what he is offering... that he's going to abdicate his elected role and divest the decision making power to a group of 168 college students? And why 168? And... oh never mind.
Back when the way you swapped samples for your sampler was mailing CDRs across the country, I ended up befriending a dude about 15 miles away. He loved k-pop back before BTS was born. Interesting guy. Anyway I'm leafing through the voter guide and there he is, the libertarian candidate for lieutenant governor. So I call him up despite the fact that it was 10:30 at night. "Dude - you're running for lieutenant governor?" (yawns) "Uhm... I think so?" "No dude you're right here in the voter guide." "Oh yeah. yeah, I am." "As a libertarian?" "Yeah dude I go to their meetings. Someone's gotta run for everything. We draw straws." "You drew the short straw so now you're the libertarian candidate for lieutenant governor?" "Yeah!" "Uhm... okay. So why should I vote for you?" "'cuz we're buddies!" "Yeah but do you have like, policies in mind or anything?" "Well we're against big government." "...gotcha. Lemme think about it." He was not elected lieutenant governor.
Yeah I think you'd need a transition period. It's still a winner-take-all election, so people will generally split along the two party lines. Multi-member districts with rank-choice voting (at least in theory) break the winner-take-all approach. That dude is awesome though. I might vote for him anyway, since he has many of the powers of Jefferson.