This is one of my challenges also. There's been a push for minimalism recently. I'm thinking of the shadowdark hex crawls. No doubt they're easy to get to the table. But so much is ill defined I feel I'm doing the majority of the creative work anyway.
I like Hemingway's iceberg theory quote in this regard:
If a writer of prose knows enough of what he is writing about he may omit things that he knows and the reader, if the writer is writing truly enough, will have a feeling of those things as strongly as though the writer had stated them. The dignity of movement of an ice-berg is due to only one-eighth of it being above water. A writer who omits things because he does not know them only makes hollow places in his writing.
It doesn't matter if most things you prepare don't see the light of day. Because having prepared them will give you a greater understanding of the world, and cause the things you do present to feel that much more real.