I meant to link earlier to Jeremy’s helpful post on Elizabeth Johnson’s book on the saints, Friends of God and Prophets. Johnson argues for a reformed, “companion” model of the communion of saints, as contrasted with the more traditional “patronage” model.
According to Johnson (per Jeremy’s summary; I haven’t read the book), just this kind of change was set in motion by Vatican II, bringing the Catholic understanding more in line with the critique made by the Reformation. Of course, whatever the Reformers’ revised understanding of the communion of the saints, actual practice in most Protestant churches has probably been to neglect the idea altogether. (Although, I do think that for a lot of Protestants, Old Testament figures actually function in a way similar to the saints.) In any event, Jeremy’s post made me want to read the book, which I think I’ll try and get from the library.