I thought the following was an interesting note made by Bruce McCormack with reference to a distinction that Alexander Schweizer made between Lutherans and the Reformed relative to what they believed to be the material principle of the Protestant Reformation.
In Schweizer’s view, what distinguished the theology of the Reformed churches from Lutheran theology was, initially at least, a differing Grundrichtung. Lutheran theology concerned itself above all with overcoming and eliminating from the church every last vestige of “judaizing”—the teaching that justification occurs through works. Reformed theology, by contrast, was centrally concerned with the “paganization” of the church through the divinization of the creature (e.g., the fundamentally polytheistic worship of Mary and the saints, the sacralization of nature in the Eucharist by means of the doctrine of transubstantiation, etc.).
Out of this initial difference in Grundrichtung, Schweizer argued, there then arose a further difference in “material principle.” According to Schweizer, the material principle of Lutheran theology was the doctrine of justification by faith alone whereas the Reformed churches it was the sense of “absolute dependence on God alone” (which was articulated dogmatically in the doctrine of predestination). Again, this difference in material principle signals a difference in orientation: the two principles in question are directed to two different basic questions which determine the shape of theology taken as a whole. The Lutheran question was, What is it in humankind that makes us blessed? and the answer given was faith, not works. The Reformed question looked in a very different direction. It asked, Who blesses or damns, the creature of God alone? and the answer was, of course, God alone. Therefore, Schweizer concluded, the material principle of the Lutheran Church was anthropological in character; the material principle of the Reformed churches, theological the strictest sense.
If this is the case we might see how this impacted the way Christology developed in the distinct ways it did for the Lutherans and Reformed respectively (which of course was most finely illustrated in the eucharist debates). But if this general identification by Schweizer is correct it might help us to further appreciate how the Lutherans came to emphasize the communicatio idiomatum, in their Christology, whereas the Reformed emphasized the extra Calvinisticum; with the former emphasizing the below and allowing that to condition their relative emphasis of how they thought the hypostatic union, and the latter emphasizing the above.
Just a quick reflection before I head off to bed; good night.
 Bruce L. McCormack, Orthodox and Modern: Studies in the Theology of Karl Barth(Grand Rapids, MI: Baker Academic, 2008), 43-4.