Could be they are giving constructive criticism because they view you as a future resource and want to keep you on their list of potentials for future projects. Sounds to me that they liked something about your writing, lyrics, arrangement, style, etc... "the music and lyric was authentic to..." Apparently, I'm speculating, you hit on most of attributes they were looking for in the instruments selected. The vocal is always the most criticized part of a song. Perhaps choosing the appropriate vocalist would make a difference also. I put my own voice on songs I arrange for other song writers with the suggestion of what type of vocalist might work best if they are pitching the song. But, they most often pitch them with my sample vocal/voice or their own voice which, in my opinion is not always the best way to go.
Anyway, how to I/we get to hear it? Do you have a link?

Does the noise in your head bother me ?