I fail to see the point of a 57-member assembly when the councillors are elected on party lists in a single district with a 5% threshold. They might as well have 19 seats. That's a 3x bloated collection of parasite councillors.
If I were King, I would make each of the 21 districts of the city elect two councillors on personal votes with single transferable voting, and 15 on city-wide party lists to improve overall proportionality. Bush is a symptom, not the disease.