Listen to the Nestingen piece here: http://gnesiolutheran.com/lectures/
This is very typical of Nestingen's style in class when I took Lutheran Confessions from him.
Any how, I think it's not a bad talk, but I think I would object to a couple of things. For one thing, as a child of Forde and the Luther Renaissance, Nestingen draws false distinctions between Luther and Melanchthon.
According to him, Melanchthon starts with the doctrine of creation and a strucutre of Law and then fits Christ into it. That's why, according to Nestingen, Melanchthon couldn't accept bondage in the end because he felt that it denigrated creation and the law. Luther starts from the cross and then reasons his way back to sin and creation.
Now, let's think about this- what exactly is he basing this on? He talks about the Bondage of the Will alot. But is this Luther's method there? Not really. Luther starts with natural theology and tells us that if we just relied on our reason we could figure out that because God exists and because he's the creator, he must be the supreme casual agent and all creatures must possess a derivative ability to act as causal agents. He does of course move on to Bible exegesis, but he mainly argues about proof texts for bondage and destroys the hermeneutical non-sense that "should" means "can." He does of course also say (more in passing than anything) that none of God's promises could be trusted if he didn't have infallible foreknowledge. But the cross really doesn't come up too much. Neither is the argument from the promise of the gospel the major rhetorical strategy. So, so much for that.
Another thing that should be mentioned is that Robert Kolb has pretty much clearly demonstrated that Melanchthon was more worried by the fact that people would fall into fatalism if Luther's view of bondage was held. So there was clearly a pastoral aspect to Melanchthon's view. On top of that, he was afraid of the rising tide of Epicurean and Stoic thought that was becoming popular during the Renaissance. So, Nestingen is not really correct on the historical basis of Melanchthon's theological views, even if he is correct that they were bad theology.
Furthermore, when I had him in class, he also used to contrast Luther's supposed method of starting from the cross and Melanchthon's ordering of the Augustana. Melanchthon starts with the Triune God, moves to creation and sin and then to the cross.
But again, how is this any different than the catechisms? In the catechisms, we have the first article and move to the second article. Of course, you could make the argument that Luther doesn't really talk that much directly about the Fall, and that the Fall is spoken of on the basis of what Christ has saved us from. Nevertheless, we're not disputing that sin's depth can only be known at the foot of the cross- Luther says this many times. We're disputing that Luther's method begins at the cross and moves backword, thereby adducing creation and sin from redemption. Again, this doesn't seem evident to me. Neither does it seem evident in the Heidelberg disputation, the Galatians commentary, the Genesis commentary, Two kinds of righteousness, The Freedom of a Christian, Against Latomus, etc..
In the end, what I really see going on here is a post-Kantian Protestant dogmatic move that has very little to do with Luther. In other words, if you follow Kant and believe that you cannot know the ding an sich, then you will have to start at what is within your own inner experience- that is redemption- and then move back using deduction to get to the articles of creation and sin. Since the Bible or the traditional theistic arguments are not automatically valid (as they were for Luther and Protestant orthodoxy), one can only get to the unknown quatity (sin and creation) from the known quatity (my inner experience of being redeemed from something). More or less, every modern Protestant theologian (that is, other than the repristinating theologians) has gone this direct in the last 200 years. Therefore it is not terribly surprising to see people read it into Luther.