The Eucharist and Reconciliation in Diversity
This document, still worth reviewing, from 1979, shows the connection between liturgical imperatives and sacramental theology. On Article XXII, see sec. 76 of this document for some concluding remarks. I think they are all on the mark because they do not see ecumenical future in straightforward agreement on doctrine. They do not expect their ecumenical encounter to persuade the other party to their own position.
As the Second Vatican Council has taught, there is a hierarchy of truths, so that certain matters are of course more important than others. Agreement in doctrine touches only one level of churchly communion because unity in the sacraments and the preached word are of a different sort of thing than doctrine. Reconciliation in diversity finds unity in such things as the sacramental life of the church and only secondarily in such things as doctrine. Thus, we do not have to agree on this or that theory of Jesus' presence but instead act in such a way as to respect legitimate diversity and true unity. The liturigical imperatives that encompass such a unity are such things as the consumption of all bread and wine in the service. This usage does not commit Lutherans, especially given the diversity of approach to the extent of the presence of Jesus in the Confessions, to any one of the views, but it does allow for a common practice of the sacrament, satisfying the Tridentine decrees and the Lutheran Confessions.