There’s so much going on here; clearly a lot of feelings and thoughts swirling around and plenty of history between commentators. Again, I have to vivisect and respond only in part.
Dr. S. is correct and valid in his comment about Lutherans historically affirming some indefinite knowledge of God and our being very skeptical of claims concerning knowledge of God beyond the purview of Scripture. You were too hasty in deeming his comment nonsense. To affirm yet remain skeptical on matters of natural theology is very much a part of the Lutheran tradition. Practically speaking, inasmuch as ID makes claims about God/inasmuch as you have related the “designer” of ID to the God of Christianity, Lutherans ought to be antagonistic. People make numerous claims about God in the world and most, if not all of them (which are not illumined by the eyes of faith in Christ and informed by Scripture), turn out false or inconclusive. Therefore, it is an unnecessary risk to place any “eggs” in the “basket” of ID. It has no positive function for Christians and very likely is a negative/false and therefore a stumbling block to the proclamation. I say “very likely” because, another facet of Lutheran theology, is respect different realms of knowing and not seeking a unified “theory of everything”. Thus, when the majority of scientists engaged in discussions about evidence for ID, who are experts in their realm/way of knowing, state that ID has no ground to stand upon (here, @swamidass becomes more an expert than myself), a Lutheran theologian is apt to defer to the opinions of the scientific “jurists”. All of this to say, Dr. S. is right about the trends in Lutheran tradition. We are skeptical because, not only does it not drive toward saving faith (as you, yourself, agree), it hinders proclamation by making inflated and speculative assertions about God (inasmuch as an ID’er like yourself connects the designer to the Christian God, which you have above) which are very likely to be false. (Recall an earlier comment I made: ID makes assertions about God which I need not accept and it makes assertions about God which may, in fact, be well worth rejecting.)
You are right to point out that Lutheran theologians have been less than friendly to permutations of the Fundamentalist Movement. We have always been for symbolic/creedal summaries of faith; for succinct confessions and confessional subscription. But the Fundamentalist movement, from its outset, was always suspect in the eyes of Lutherans. If I could use a broad, sweeping, generalization; it leaned too heavily on the capabilities of human reason and empirical investigation in an attempt to counterbalance the “liberalizing” trends emerging in the mainline church bodies.
As applies to ID, again, we are infinitely cautious because ID is an attempt to bring something about God (the designer) into certitude and outside Christ. Some have used it to assert we can know with empirical certainty where God acted in history (see my reference to Dr. Barry above). To those less enamored, such as myself, the risk and temptation is apparent: to begin founding one’s faith not on the “Rock” but on “shifting sands” and speculative connections between theology and science. For example: what happens if Dr. Barry’s very confident claims about ID backing up creationist stances based on the second law of thermodynamics is demonstrated to be fallacious and bad science (and fallacious it very much is)? What happens is that Christianity is unduly scandalized and people are given what they think is a good reason to ignore the proclamation. @eddie unabashedly connects ID to the Christian God, even if he says ID is not, of necessity, religious in its claims. He proposed the existence of scientifically verifiable evidence of a designer of the gaps and ascribes to God the accolade of this Designer. But what happens to the Christian proclamation when these gaps are shown to not be gaps? I would remind you that we are dealing with eternities here.
But I will say I am likewise skeptical of people who think they can mesh science and theology in different ways, as well. Like those who think they can fit evolutionary theory, without conflict, into the Christian worldview. Instead of peaceful coexistence, instead of founding one on the other, instead of bringing a unity to them (as some EC, ID, and, even more so, YEC people are prone to do), Luther and Lutherans draw a deep line between theological claims and scientific claims and let the tension abide.
When Luther looks at the fields of the jurists, the economists, and the doctors, as a theologian, it is not with the intention of justifying their concepts anew, reordering them, or even aligning them with Christ and the gospel. Rather, just as he vigorously demanded concepts transferred from the secular realm into the spiritual be critically examined, so too he equally insists that secular things be allowed to remain secular and not be qualified anew retrospectively, on analogy with soteriology.
Theology the Lutheran Way, page 78
”For all created things such as the sun and moon, are for Christ and are not against him, because all things work together for good with the godly, even the evil, death, and hell. But you cannot conclude from this that truth is the same in theology and philosophy, for they will continue to be different in kind and in matter,” until the eschaton.