I can think of a lot of songs that might fit. But, in reality, it has a lot more to do with repetition and quality of performance than any other factor. "Kumbaya" gets nominated a lot simply because it's been done to death, and by some horrifically bad performers. The same can be said for some other pretty good, and historically interesting and significant material. It's the "dead horse" syndrome. Also, most performers are likely to be a lot more critical than ordinary audiences when it comes to overused songs. I don't know how it is elsewherein the world, but it was once said, possibly by H.L. Mencken, that "no one ever went broke underestimating the taste of the American public."