Marching band, on the other hand, has a perceived history of being primarily a "Brass & Blast" ensemble...with woodwinds usually reduced to a vestigial component of the ensemble, and in some bands eliminated completely (Ohio State, for example). People are wanting to hear a more balanced ensemble sound coming off the field now, and the marching sheets reflect that in order to encourage that balanced ensemble sound.
In any case, not having a solo or exposed WW part doesn't mean that the section isn't being used effectively. If you have a solo/exposed WW part, and it is being performed poorly, can you honestly say that the woodwinds in that band were being used effectively? The answer is most definitely "no". In this case that exposed part is a detriment, and the band would lose points there.