Zoltan Kodaly was a great music educator who created a whole generation of better musicians and better music teachers through his comprehensive method. There are many things about Kodaly's method that resonate with my own curriculum planning, but there is one major thing and one minor thing that I believe he got wrong:
One of the biggest issues that I have with Kodaly's method is how music teachers have to change old folk song melodies to fit the proper solfege progression, simple things like leaving the fa out of "Hush Little Baby," and many more examples. Second to this is how some songs have completely changed or how so-mi patterns have been added to chants as if they had always been that way. In other words, there are many examples of Kodaly-music that are not authentic music. Granted, I may be misunderstanding how the Kodaly method works, but I feel like even kindergarten students should listen to and sing songs that include all the notes of the scale, not just so-mi-la.
The other minor issue that I have with Kodaly is that he leaves out an important source of music: student- and teacher-composed songs. I completely agree that music to be studied should come from culturally and historically authentic and significant sources, and that high quality Western Classical music should be part of the curriculum, but it seems like Kodaly excludes the idea of creating a song specifically for the students or specifically for teaching a musical concept.
There are many things about the Kodaly system that I like and agree with, especially the concept of experience-before-theory, and I plan on using some of Kodaly's ideas every day in my lessons, but maybe because I'm just stubborn, I plan on finding my own collection of songs to teach through.