Some of it already has been.
Aside from the Arts Industria releases that contained "Graverobber"
& "The Drowning Season", one can find very early versions of the
tracks "Purgatory"on the Arts Industria "Silicon Warfare"
compilation, and "Coward" on the "Voltage ][" compilation
compiled by Suicide Commando's Johan Van Roy. Pre-signing cover tracks "I
Ran" [A Flock of Seagulls] and "Love My Way" [Psychedelic Furs]
can be found on the now out-of-print 21st Circuitry Records compilations "Newer
Wave" and "Newer Wave 2" respectively. "The Drowning Season"
later found it's way onto the "Addendum" remix album in 2001 (Europe
only on Accession Records). A few years ago, the previously unreleased 1995 track
"Underneath the Ice" appears as the b-side to the 2002 "Document"
single (again Europe only on Accession Records).
However, it wasn't until 2007 that a significant amount of early A23 material would see release, albeit in re-recorded form. Specially created for A23's 2007 US tour, "Assemblage 23: Early, Rare, and Unreleased 1988-1998" is a limited edition (of 1000) CD containing re-recordings of 14 of Assemblage 23's early, and mostly unheard works.