I wouldn't worry too much about human readability so much as human usability.

The proposed two-column format allows for a trivial CTRL-F to locate any specific desired one-off info, should someone want/need to find something directly in the raw CSV file (most likely looking up by addr or by label text).

And I don't think it's a reasonable use-case/design constraint to try to insure that the format be easy for humans to directly edit or add to themselves. Manually logging inputs or outputs is going to be incredibly error-prone regardless of how the format is defined. Excel or Google Sheets is fine as a convenience viewer, but manual editing only really makes sense within some kind of dedicated Bitcoin-savvy helper UI that can look up each txid entered, etc.

Ongoing management via direct human edits isn't practical (or at least wouldn't be a recommended practice) so let's not agonize over it.