It has been said that the center/focus of the protestant worship service is the preaching, while in the roman (catholic) tradition the center/focus is on the Eucharist (communion). I wonder if this comes from the legacy of Luther and a reaction to problems in the Roman church. Luther himself did not want to split the church, but merely reform it’s doctrine and practices. However, since then the church has split and doctrine has become the primary focus of protestantism. Traditionally there have always been different thoughts and ideas about the specifics of doctrine; the problem of making doctrine central is that now those with differing ideas won’t fellowship with each other. This has caused protestantism to fracture in to thousands of separate churches each based on different shades of theology.
I believe the focus on doctrine is the reason for the centrality of preaching. I feel that many protestants are on dangerous ground, appearing to have built an altar to a specific theology. I think that shifting the focus of the worship service from Christ and communion to preaching (or in some cases praise music) is a telling sign that doctrine (or an experience) may have become too important to us. That said, I certainly believe that teaching is quite important, and it is possibly a lack of good teaching which has brought us to this position. However as far as core beliefs, I believe that we should return to the creeds (and the original Nicean creed specifically), which for centuries have defined the Christian faith.