A certain James Swan has taken it to himself to refute this old change and he has done extensive research and has ample documentation to suggest that this is not as simple as it seems and that Luther cannot be so cavalierly dismissed. You can read it here. I have summarized Luther's points below.
“If you are a preacher of grace, then preach a true and not a fictitious grace…” “…if grace is true, you must bear a true and not a fictitious sin. God does not save people who are only fictitious sinners...” “Be a sinner and sin boldly, but believe and rejoice in Christ even more boldly, for he is victorious over sin, death, and the world.”
Unfortunately, some Lutherans have not gotten the point. They missed the second part of Luther's words: if grace is true, you must be true and not fictitious sins. It is not only that do commit a lot of fictitious sins; we confess a lot of them, too. Not so long ago I was at a churchly event and the script (cannot bring myself to call it a liturgy) did just that -- it led us to confess fictitious sins and kept us from confessing the real ones. Gone were the words about sinful nature and uncleanness. Absent was the usual "thought, word, and deed." Missing in action were the familiar "by what we have done and by what we have left undone." We were not miserable at all. We were failed but not irredeemable.
Lord, too often I have tried to make it on my own and failed miserably... If only I had tried harder, maybe I would not have failed so terribly -- it was not my sin that made me miserable but that I did not succeed in this sinful isolation... leaving a path of hurt and disappointment behind... Oh, yes, I cannot ignore the folks who were counting on me to succeed and whom I disappointed and scandalized by my inability... I have lashed out at others and even at You when my foolish plans have gone wrong... No good blaming others or making them bear the burden for my inability. The same for God. I should have succeeded and I screwed it up and I should not have dumped on others for my inability... Father, help me trust in Your strength, learn from Your wisdom, bow humbly before Your throne of grace... If only I had a little more faith, knew the Scriptures better, and was not so proud, I could succeed and I would succeed and then I would not have to be in this position... Help me to stand firm in my faith... let me boast of nothing but Christ's righteousness... If I work at this with Your help, I can fix it and I won't be back here on my knees like I am now...
Okay... snark off mode. Where do such words of confession intersect with the Commandments? Where is the acknowledgement of mea culpa, mea culpa, mea maxima culpa? Where is the awareness that sin is not just lack of good but real and unmistakable evil -- in the heart as well as in the life? We are too good at framing confessions as failures of will to do what we should or be who we ought to be. We need the real words of the confession to remind us that sin is not simple lack, it is the captivity of the heart, the reign of evil, the friendship with the devil, the world, and sinful nature, and death. We need to confess that we have done something and not that we did not try as hard as we should or do as good as we might have done.
Snark mode on... But, dear friends, for fictitious confessions of fictitious sins, there are fictitious absolutions as well.
Back to earnest words... Why is it so hard to simply say "I forgive you all your sins in the name of the Father and of the Son and of the Holy Spirit?" We don't need different ways to say something similar. We need to say in the clearest and plainest way possible (as does the absolution in the hymnal) "I forgive you..." This is part of Luther's contention -- confessing fake sins and receiving fake absolution gains you nothing. Sin bodly. True repentance means honest acknowledged of what sin is, of your sin, and of its consequences. The fruit of true repentance is this honest confession (which itself is the fruit and work of the Spirit in you). And the response of God is true absolution -- in unmistakable terms as red as blood and as real as the cross. That is what Luther contended for and what some of us Lutherans have forgotten...