Tough question wylie. Are you speaking in a compositional framework, or just appeal?
I'll only say that a in a good song containing lyrics, the lyric (the "voice") and the melody should speak to, or with, each other.
But, in general, a good (or great) song is just a "tune" that has stood the test of time, and thus appeals to wide audiences with differing personal lifeways.
So someone listening to a tune (for the 1st time) living in the 50's would like it, but someone living in the 20's, or the 21st Century would also like it.
USUALLY, for that to occur, the melody need by simple but have a strong hook(s), so it sticks. becomes an ear worm easily.
Those are all LARGE generalities.