I suppose my fundamental point in the post below is that the desert is not merely the trivial detail of John's ministry I had always taken it for, to the extent I took it for anything. It was part of the unfolding of the Gospel, something important enough to be foretold by the Prophets.
We must always first recognize that something means something, before moving on to what it means. The Church Fathers were a lot better at this recognition than I am, even if they do seem a bit fanciful in their exegesis; e.g., Theophylact on John the Baptist's diet:
The food also of John not only denotes abstinence, but also shows forth the intellectual food, which the people then were eating, without understanding anything lofty, but continually raising themselves on high, and again sinking to the earth. For such is the nature of locusts, leaping on high and again falling.
But to have an open and humble disputation on the significance of locusts and wild honey, we need to first acknowledge that there is a significance.