I understand the dried cranberries but what did it for me on this was that there wasn't so much of a contrast between the "dried" fruit and the sweetness of the miracle whip and sugar.
The vinegar provided a nice cut to the sweet flavor profile. Regular raisins wouldn't have done it as nice as the "golden" raisins. Different taste altogether. To me this recipe is perfection, best I've ever had, and I'm not messing with it.