The Kansas City Star has this op-ed by Larry R. Bradley about the initiative for a top-four system currently circulating in Missouri. Bradley supports ranked choice voting, but he criticizes the initiative, both because it eliminates the ability of parties to have nominees, and also because it seems obvious that if ranked choice voting is so good, it should be used in primaries as well as general elections.
Bradley does not mention another flaw in the initiative, which is that it makes it almost impossible for a third party to become or remain ballot-qualified. This is because if parties don’t have nominees (except for president), they can’t meet the vote test, except for president. Currently the typical minor party that gets on the ballot in Missouri is able to remain on, because it isn’t that difficult for a minor party to poll 2% for one of the lesser statewide races, such as Auditor or Treasurer. But under the initiative, the only office for which the vote test would still work is president, and it’s extremely difficult for minor parties to poll 2% for president. The Libertarian Party has only done it once (2016). The Green Party has only done it once (2000). The Constitution Party has never done it.