This would be the simplest to write and read, but would really hold just one single profile on a single set of pressure levels. This is less than some core-Argo files (which can hold multiple profiles from a single cycle)!
Single-profile format is a very inefficient way store, transfer and read in large numbers of profiles.
Providing WOD data in single-profile netCDF files via WODselect is "by far the biggest drag on our system", requiring the netCDF files to be archived, selected and zipped on request, rather than being generated from the database.
IQuOD will (initially) have an order of magnitude more profiles than Argo, so it makes even less sense to maintain them in single-profile format.
This would be the simplest to write and read, but would really hold just one single profile on a single set of pressure levels. This is less than some core-Argo files (which can hold multiple profiles from a single cycle)!