So I proposed to her that I add a design on the front of it--I had suggested a hot air balloon (it seemed to fit the stain's shape), but she countered with butterflies. Butterflies work.
So I happened to have some green jersey knit in about the same shade as the shoulder buttons, so green butterflies it is. After a fair amount of trial and error (and ripping out and repairing the rips and judicious use of fusible interfacing and stitch witchery), voila! we have four appliqued butterflies, complete with stitched antenna. And now the dress is way cuter.