It's on! - but it takes some time to formulate a thoughtful, considered response. The more I think about it, though, I am becoming more sympathetic to your viewpoint. But there do seem to be problems, as well as other viewpoints, making it difficult to decide just what to do.
I suppose one of the largest hurdles to be dealt with is ... tradition ... that and the fact that contributors/editors (and sometimes composers themselves) are the ones that supply a voicing that, in terms of the "minimum number of voices" (MNV) required to sing a work. For example:
(1) The last-act Finale from "The Gondoliers" ("Dance a cachuca, fandango, bolero") by Sullivan is described in the E.C. Schirmer edition as "for four-part chorus of mixed voices" - but, in fact, each of the SATB parts divides at some point into two parts. Should this work be voiced as SSAATTBB? or SATB? or (since there are never more than 6 different parts being sung at once) something else (maybe SSATTB or SSATBB)?
(2) Mendelssohn's "Elijah" is given the blanket voicings SATB and SSAATTBB at ChoralWiki and just SATB in at least one commercially available edition ... in both cases, these seem to ignore the voicing for the lovely SSA terzetto "Lift thine eyes". Indeed, should larger works with different voicings have their movements separately voiced? (I think so.)
(3) In Renaissance works for which the "full" or "tutti" voicing is different (usually smaller in number of voices) from the solo sections (including gymels) how should the voicing be done? - separate voicings for full and soli, or voicing for the minimum number of performers necessary to sing the work (full and soli lumped together) since, in early music performance practice, it might be argued that such works were sung with relatively few voices? In a work such as the Tallis "Gaude gloriosa" the tutti voicing is 6-part SATTBB, but there are S, A, and B divisions (gymels), yet at no time are there more than 6 parts singing at once - so the work can be performed with as few as six singers (especially if one of the basses or tenors also doubles as a countertenor - which happens); moreover, we cannot be sure that the gymels were intended to be sung one on a part (I've sung the work in performance where the S and A gymels were sung two to a part, 8 singers total, plus two on the accompanying bass part, and the B gymel was sung one to a part, 2 total).
(4) There are numerous works in which doublings (usually at the octave) are written but not specified in the voicing, eg. notes below the bass clef in a bass part which are doubled at the octave, presumably for basses/baritones which cannot sing that low - but the composer's intent is not clear. A similar treatment might be having a bass subdivision at the fifth for a cadence, where the fifth might be (justifiably?) omitted in some cases. One sees inverted versions of this situation in soprano (occasionally tenor) parts where the part subdivides with very high notes (above the treble clef), usually at a cadence, with a probable(?) intent that the high note(s) are optional or possibly(?) that the lower notes should only be taken if there are no singers able to sing the higher ones ... again a very murky situation in terms of voicing and MNV.
In general, it is presumably the case that performance (however adequate or scholarly or suited to the occasion) usually trumps the written score ... we already see that in transpositions of works. For example, it is not at all infrequent to see low basses take a final tonic down an octave - nor for a piece to be given a rousing fortissimo ending with sopranos or tenors taking a higher note in a final chord than is written in the score ... all (I assume) for effect. And there are even editions of works (eg. the Allegri "Miserere mei") which spell out performance practices that have little to do with the original Allegri music) ... but here, at least, one can specify the voicings, although does one specify the tutti (chorus) and semichorus (solo) voicings separately or lump them together in the MNV spirit (the two groups might be physically separated in performance/liturgical use)?
Another problem is one of what I'll call (for want of a better term) "musical intent" (stemming from the genre and intended performance setting of the work). Would/should (1) above ever be sung by an octet or (minimally) a sextet? I don't know ... maybe in a production with a shoe-string budget?
Is there a way for voicing and number of voices to be "all things to all people" - or do we have to make some sort of compromises? Short of having (perhaps hidden) voicing categories for MNV separate from voicing categories based on usual performance expectations, I doubt we can satisfy a significant majority of users. Any changes we make will also require some advance notice and probably entail a significant transition time whereby qualified volunteers work their way through the CPDL collection.
I have other thoughts about varied performance practice and evolution (along the lines of the evolution of the Allegri) - at least one of which stems from the Samuel Barber "Adagio" legacy ... as the second movement of his String Quartet, Op. 11, then as an orchestral arrangement for strings, then as a choral work "Agnus Dei" (which is an 8-part work). I'll probably have more to say down the road a bit.
Additionally, although I think any decisions to be made and actions taken should be administrative, I think we might benefit from having this discussion being conducted in a wider forum.
Chuck
Edit: I just looked through music for an upcoming concert with a local community chorus and findl (all listed voicings occur in the score), in addition the "The Gondoliers" chorus cited above:
* A "Rogers and Hammerstein on Broadway" medley lists itself as for "SATB voices and piano with optional instrumental accompaniment" - but, aside from solos within the work, the has (in places) subdivided Alto and Bass parts as well as one place (with the basses already divided, an optional divisi high note for tenors). Should such a piece be voiced as 6vv SAATBB, or even 7vv SAATTBB?
* Randall Thompson's "The Last Words of David" (E.C. Schirmer) lists itself at the beginning of the score as "for four-part chorus of mixed voices" - although the basses and sopranos subdivide near the end (and basses once at an earlier cadence). Is this piece then for 6vv SSATBB?
* "River in Judea" by Jack Feldman, arr. John Leavitt, says S.A.T.B. on the title page but has SATTB, SATBB, SAATBB, and SSATTBB moments (the last at the very end). Should the work be voiced 7vv SSATTBB (the maximum parts at anyone time) or 8vv SSAATTBB (since the altos also divide briefly elsewhere)?
* "Danny Boy", arr. Mark Hayes, is "Level Five SATB with Piano" and actually has a flute part, and has 3-part men's as well as 3-part women's subdivisions (hard to tell whether SSA or SAA and TTB or TBB). So is this work a 6vv piece with something like SSATBB voicing (or other configuration)?
Just some more grist for the mill.