Comment by stakhanov

I'd say, it's useful to distinguish between intentional and unintentional ambiguity/underspecification. For example, many jurisdictions that have statutory contract law have a statute that says that a provision in a contract is unenforceable if it is "unconscionable". There is, of course, a broad spectrum of things that can fall under that term, but that's intentional, i.e. the law maker specifically wanted to open a door there for a judge to hold a contractual provision unenforceable if they need it to be to get to a just outcome.

However, a lot of ambiguity, underspecification, and just plain sloppiness in language is there for no good reason and causes problems, and it would obviously be a good thing to get rid of that.