The contemporary ballad is much more private and sorrowful, less taken up with public address than private feeling. The pantoum began in Malaysia. It became popular in Britain and France in the nineteenth century. Then its slow rhythms and offbeat repetitions began to appeal to poets in the twentieth century. The poet's voice is a key element of form.
Some forms change it so much that they almost seem to be voice filters.
The villanelle, for example, resists narrative, but the ballad highlights it. Mark Strand's introductory essay doesn't mention any of the forms discussed in the anthology. Again and again the editors return to the power dynamic implicit in many of the forms discussed. Find evidence of this in the poems themselves. Closer inspection, however, reveals changes in both the letter and the spirit of the rules of form.