Just as a specific example:
(original)Bring us out a mouldy cheese
And some of your Christmas loaf"
(new improved version)
Bring us out a mouldy cheese
And some of your Yuletide loaf"

I am being asked to believe that this is an improvement. I disagree. And:
O Yuletide tree
O Yuletide tree
To sus you are so lovely.
I think that is unsingable doggerel. But I fully agree, one man's doggerel is another's poetry. I remeber well the editors of the Oxford Book of Carols(mainly Vaughan Williams) expressing the view that "Good King Wenceslas" was unsingable doggerel, and hoping it would soon drop out of sight. Well, their wishes weren't granted. Mabe people will be singing "Oh Yuletide tree to us you are so lovely" in their millions in a hundred years time. Who knows?