An interesting question...however I think how the general lack of
availability of playback hardware makes a recording a candidate for
reformatting.
Perhaps I misunderstand the function of an archivist, but reformatting
to preserve information would seem to be an appropriate role. Not that
one would choose to use a format expected to be obsolete in years (or
decades), but one should not look to the immediate transfer as the last
that will ever be needed.
Will WAV outlast FLAC? Probably. Is the storage saving worthwhile under
the circumstances? That depends on the archive and its purposes. For
example, if the purpose includes making copies for loan or other
distribution, there might be an advantage to using lossless compression
and including a player of some sort and related material - text,
graphics, what have you - on the CD-ROM with the audio. That can be done
while providing perhaps 120 minutes on each disc. Doing the same on
DVD-ROM in ISO 9660 format would permit more substantial works to be
offered.
I've been using low-rate MP3s for reasons not related to archivists'
functions for more than a decade. On any Windows system, the disc
includes a browser with MP3 capability so that it autoruns and supplies
supporting data. Indeed, four of those discs can be seen on the WWW in
the form used for the CD-ROMs: http://www.ucis.pitt.edu/opera/