In NYC, this is a democrat protection scheme.
In a few elections, one republican runs against a field of democrats. There's some concern that the Republican might win against a splintered field of Democrats -- can't recall it ever happening, but the Republicans, who are a small minority, are forever hopeful.
That's a feature, not a bug. Fair minority representation requires multi-member districts. I understand democracy as implying majority rule, and where there is only one winner, that should have majority support.
There should be multi-member districts where possible to avoid one-party domination, but in cases where there can be only one winner, isn't it democratic to allow a party with majority support to win?
Kind of depends if you believe that representation depends on people vs party. The party apparatus is controlled in a not-particularly democratic way, which strongly affects who gets on the ballot, and historically it was possible to win a major election with about 2% of the population of the district voting for you.
There was another proposal a few years ago to make local elections non-partisan.
Random ballot elections are the most representative.
This will ensure that none get elected.