I think the "monster maroons" were, in fact, intended to be the dress uniforms, it was the addition of vests, field jackets, skirts etc. that made the basic design more versatile and functional in different cicumstances?
That's an interesting idea, and I think it's plausible even though we never saw the shirts worn without the dress jacket. My only wish for the TWOK scheme would have been to keep the original color scheme for the shirts, rather than the new one that was invented.