I do this all the time but then you end up with really over engineered code that has way more issues than before. Then you're back to prompting to fix a bunch of issues. If you didn't write the initial code sometimes it's difficult to know the best way to refactor it. The answer people will say is to prompt it to give you ideas. Well then you're back to it generating more and more code and every time it does a refactor it introduces more issues. These issues aren't obvious though. They're really hard to spot.

You can, and it might make things a bit better. The only real way I've found so far is to start going through file by file, picking it apart.

I wouldn't be surprised if over half my prompts start with "Why ...?", usually followed by "Nope, ... instead”

Maybe the occasional "Fuck that you idiot, throw the whole thing out"