I found the idea of a password generator appealing, mainly due to vault anxiety. I didn't (and still don't) like the idea that I can't access a resource without this precious vault. If I'm home with my tools, great. Otherwise, give me the right hash function, and I can MacGyver my way to PBKDF2 and generate my password.

However, once you introduce metadata (e.g., to deal with password rules), the idea loses most of its appeal. I wouldn't feel any more comfortable posting such a thing publicly than I would a vault.