A rewrite from scratch sounds good. The main thing I've been anticipating is better looking shorelines, which you mentioned awhile ago; I take it that's been too hard with the present codebase. I don't know how a rewrite would/should affect Azgaar integration; for myself, if I'm concerned about saving exactly how a city looks in an Azgaar map, I generally save it as an image. But if people have concerns about stability (like the comment here about districts), I could see benefits to keeping the original city generator available while posting the newly rewritten one.
I continue to be oddly fascinated by this tool, it's so satisfying. Also I'm sure countless RPG groups have explored your cities without necessarily leaving any comments. Here's to many more years of random cities!