There is value in challenging music. But there is also valuable in music that is easily sight readable.
In fact, I think that one of the reasons the Parker-Shaw choral arrangements have stood the test of time, still regularly in programs decades after their premieres, is because they were intentionally written to be sight read by the Robert Shaw Chorale. The members were professional singers, but they had to record an album in just a couple days. The music needed to be interesting, but also absolutely clear on the page, melodic, musically logical.
The value of this kind of music in your repertoire list is multifold. Students become better sight readers when they sight read music that’s sight readable. Music that’s sight readable is often fun to sing, because you get right to the music of it. Sight readable repertoire can leave more time in rehearsal for bigger lifts.
I love complex music, and I love writing complex music. But more and more I look for ways to achieve all the effects I seek as simply and sight readably as possible.
(I feel like this is so obvious I shouldn’t have to say it…but so many musicians and students equate difficulty with value. They aren’t the same thing.)