You know, while I agree that sometimes compound data is problematic (and I refer, for instance, to the way options are stored in wordpress database -- they are php serialized data). Sometimes you do want an atomic value in the API.

The dsn parameter in the DBI API is a good example, it is a "connection URI" and it makes it simpler to use, the same way that typing a www URL is simpler then sending the individual parts by name... The problem is with modules that break the consistency by trying to split that data