This discussion is of interest to me because so much of my own output is called "light verse" whether I thought of it that way when I wrote it or not. I've always thought it was just because my poems were
A) Formal
B) Accessible
C) Truthful (on the theory that "mankind cannot stand very much
reality" without laughing).

Anyway, after years of writing "darkly cynical" stuff and being laughed at for my pains, I finally accepted that I was a "light verse" poet &
have been one ever since.

(PS: I'm not in the bakeoff, so it's not me you're discussing).

Light and dark are woven fine,
a clothing for the soul divine;
light and heavy have similar powers -
hellish moments push up flowers.

I'm afraid I can't be much help on this one as I've never quite figured out the difference myself. Many poets are helpful in self-labeling certain of their poems as light verse. I've always liked the original sense of the term "vers de societe" and how Larkin plays on the literal meaning of the title in his own brilliant poem. A lot of light verse is topical and thus has a short shelf-life: "not for all time but for an age."

If the world were a fair place, I'd like to see some of the poets who disparage the term do some themselves. I don't think I've ever seen an attack on the sonnet by a poet who could write a passable one.

Oh, mercy, don't say that on Erato--someone is bound to take it as a challenge!