>For one, I don't think blue, orange, and white are very compelling or locally relevant colors.

They're very locally relevant. Those are the colors of William of Orange, the Dutch ruler whose dynasty first established the city as New Amsterdam. He was a member of the House of Nassau, which is why Nassau County is so named. Those colors are used for the Mets, Islanders, and Knicks (who are named after the Knickerbockers, which was also a name for the Dutch settlers of New York).

All of that said, you're not wrong that those other flags look nicer than ours, but it's not clear to me what a better replacement would look like. The Statue of Liberty is probably our most iconic symbol, and nothing else really comes all that close, so I'd be open to seeing a design that incorporated it. The current seal on the flag should remain as the city seal, but it doesn't need to be on the flag (too small and detailed.)