Might work, but would all kind of exercises be in the same category ? Piano, Chamber, Orchestral, Band even rock bands ?
also who would decide which one is an "exercise" and which one not ? the same guy who wrote it ? don't trust very much on the self-critic of the composer, because many would say thier work is already good, and they'll post it in the "non-exercise" category, and maaaybe probably possibly one very rare composer will post something very good but due to his humility will consider it an "exercise"..
Keep talking about this and if this is indeed a necessary category I'll tell chopin.