CSVs are such a pain if you have freeform text (in which you have to handle newlines and escaped quotes).
It seems like using FS/GS/RS/US from the C0 control codes would be divine (provided there was implicit support for viewing/editing them in a simple text editor). I get that it's a non-printable control character, and thus not traditionally rendered... but that latter point could have been done ages ago as a standard convention in editors (enter VIM et. al., as they will indeed allow you to see them).