Sill, we wish he were sung a bit more.
Fact is, the guy played a crucial role in the life of the Evangelical movement, and especially in its Catholic corners. All the history books tell us that he was a leader in the Confessional revival of the mid-19th century; that he led the charge against Samuel Simon Schmucker; and that he helped to create both the General Council (boo-yah!) and its seminary at Mt. Airy. These alone would be very fine things. (He also promoted the Akron-Galesburg Rule, which sounds worse than it really was.)
But Krauth -- whose name, by the way, was Anglicized, and is pronounced Krawth, not Krowt -- did something else, which is not described as well by the standard textbooks. He helped to turn Lutheran theology ad fontes, allowing a generation to understand not only the Confessions but Luther's own writing, and indeed the Reformation as a whole, in their proper context -- not only as the beginning of modernity, but also and primarily as the climax of the Middle Ages.
In an age that saw Luther as The First Protestant, and freely remodeled him to sound like a liberal Presbyterian of the 1830s, it was Krauth who put up a hand to say, "No! Luther wore vestments and celebrated Mass; Luther treasured the Eucharistic presence and the baptismal gift of new life; Luther took for granted not merely the Virgin Birth but the Perpetual Virginity." In other words, Krauth applied to Luther a hermeneutic that would be instantly recognizable to 20th century scholarship, from Gritsch and Jenson to David Yeago. It is commonplace now, but it was revolutionary in its day.
Mind you, Krauth was not brilliantly original in this. He was inspired by J.W. Nevin and Philip Schaff, the controversial faculty of the German Reformed Seminary at Mercersburg; and they -- especially Schaff -- had been inspired by the theological faculty in Berlin, especially those liberal icons, Friedrich Schliermacher and Augustus Neander. Curiously, the Berlin theologians helped to inspire a wave of Romantic theology across Europe and America, and were then discomfited by the theologically conservative turn that it often took. (Neander went on record as opposing "Puseyism," which is funny since he had helped create it.) The difference is that Nevin and Schaff, faced with the geometrically more difficult task of applying this hermeneutic to Calvin, generally failed; they have had little lasting impact on the life of the Reformed churches. Krauth and his team helped to transform the Evangelical ones.
And we do mean to tip our biretta toward the rest of his team: his daughter Harriet; his son-in-law, Adolph Spaeth; colleagues like Beale Melanchthon Schmucker. They get a great deal of attention as reformers of the liturgy; we often think that they are undervalued for their joint contribution to the "feel" of Lutheranism in the United States, from worship to architecture to foundational theology.
Do not mistake Krauth for a mere "confessional conservative," promoting a repristination of the Reformation as he imagined it. There is plenty of that in our church, but Krauth's vision was more expansive -- and, despite that Galesburg Rule, more ecumenical. Consider his description of Lutheranism's creedal orthodoxy, from an 1850 Evangelical Review article:
It will be observed, that the orthodoxy which we now assert, is not a symbolical orthodoxy; it is not that of the Book of Concord, it is not the orthodoxy of the Lutheran church in some of its most peculiar elements. It is that orthodoxy which the Reformers found existing in the Church of Rome, derived from the primitive ages, which they could not discredit, and which was received by them and others.
Your see why we like this guy? Those words are practically a battle cry for evangelical catholicism, in its purest and least cloying sense. We will stand by them any time.