I'm probably not a confessional Lutheran in the strong sense of the term. Some folks who are "confessional" are adamant about it, fastidious in their attention to being confessional. It is a mark of pride, a crypto-fundamentalism. I don't consider myself a confessional Lutheran of that stripe.
I think I tend towards more a "big-tent" confessionalism. How to define this... Well, let's just say that in any given conversation that is ecumenical or multi-faith in some way, I let my church's confession take precedence in what I say, preach, or teach, over my own personal opinions or reflections. I hope that my own thinking is coming into greater and greater alignment with the confessions of the church.
If I fail to preach or teach in a way that is congruent with the confessions, I would strive to admit that I have failed to understand them, have forgotten them, but would like to understand them better.
I take a similar approach to Scripture. Since I consider the confessions of the Lutheran church to be a solid interpretation of Scripture, I value them highly, but I place Scripture even higher. I don't just want to read Scripture. I hope to be read by Scripture. I hope Scripture will shape how I preach and teach and believe to such a degree that my own faith will be submerged in the waters of the canon of Scripture.
But by "big tent," I mean that I offer that position with a certain humility in the wider ecumenical conversation. I don't try to disguise that I'm Lutheran in my presuppositions. But I let it be a voice in the conversation, and I assume I can learn more about my own confession by listening well and diligently to others of a different persuasion.
It is also "big tent" in the sense that I believe that the authors of the confessions were striving, in their confessional writings, to be in continuity not just with Scripture, but with the tradition of the church, especially the Church Father's and the ecumenical creeds and councils, what is sometimes called the regula fidei or the analogia fidei.
However, it is not "big tent" in the sense that I claim not to have a confession. I have trouble imagining being a pastor in a non-denominational or non-confessional tradition. I can't honestly say that I'm "just a Christian," or I just believe what the bible says, full stop. I find this position disingenuous, even if people don't intend to be disingenuous when they say it, because it fails to admit the various hermeneutical lenses that people employ when they read the Scripture or confess faith. In this way, being "confessional" is much like being self-aware about your hermeneutic, or what Gadamer called our "horizon of interpretation."
And when we are unable or unwilling to identify our horizon of interpretation/confession, it's impossible, ultimately, to achieve a Horizontverschmelzung.
So in the end, I happen to believe that being confessional is a much more open position for dialogue, mission, ecumenism, than supposedly non-confessional forms of belief. It is so precisely because it knows better how to dialogue, because it has identified presuppositions and concepts, even has a confessional text to refer to. And it has a kind of humility, because it tries to be part of a larger tradition, and subject to it, rather than individual and free-floating.
So that, at least in part, is why I'm a confessional Lutheran.