The more I read around in the history of Lutheranism though, the more I appreciate the fact that I only think their particular interpretation of the tradition and the Scripture is obvious is due to their efforts at forcing out other alternatives. Interacting with other Lutherans on the internet, even ones who are relatively conservative and claim to be confessional, it must also be born in mind that their are still many hostile to their theology. These types tend to hail from the WELS or micro-synods, and are not greatly influential. Nevertheless, it's important to recognize that either theologian is still unchallenged in conservative American Lutheran.
Hence, I would proudly call myself a Waltherian-Pieperian Lutheran.
Their three greatest contributions I would argue are in three areas:
1. Election- against the "in view of faith" position. This still pretty much rules among lay people I've noticed. Ironically, although they have fallen into other heresies, no one in the ELCA teaches this anymore as far as I can tell. At least no major theologians.
2. Universal objective justification- Against the Iowa and Ohio Synods. Later, Lenski and Reu, among others.
3. Church and Ministry- Against Loehe quasi-Roman Catholic position and the functionalism of the various Pietisms, Hofling and later the WELS.