There are a lot of voices out there telling you what kind of music you should teach. Simon Carrington says every program at an ACDA conference should include some Renaissance or Baroque music. Your state organization might insist that you program from a certain list to participate in festivals. I strongly suggest that you program more accessible jazz repertoire as part of your concert season.
But beyond all those voices, your baseline standard should be, make the music you want to make. There are countless ways to teach the musical concepts, the interpersonal lessons, and the overarching philosophies that you want to teach each year. You can teach light, dancing rhythms with a Bach motet, but also with a salsa-tinged jazz piece, a doo-wop 12/8 piece, or an Alice Parker folk arrangement.
Solfege is solfege regardless of the composer, era, or style. (Though you will probably be more successful with Part than with Stravinsky…).
Blend, balance, tone, vowels: they all remain teachable across the entire range of choral repertoire. And while not every piece will be perfect for every concepts, a well-balance year-long program will give you ample opportunities to teach everything you want to teach.
So, then, make the music you want to make. You will teach better if you’re teaching music you love, and your enthusiasm for the music you’re rehearsing will be infectious.
I don’t necessarily disagree with any of the other voices out there telling you what to program. But balance all of those voices. But make sure you take their advice only so far as it agrees with your core instincts, passions, and predilections.