Predenominationalism is Christ-centered, not Paul-centered or Peter-centered.
Are you saying that Paul or Peter are not Christ centered, or better yet, are you saying that Paul and Peter do not better represent Christ as those ordained to be witnesses of Christ??
Your approach to the doctrine of justification based upon a "Christ-centered" philosophical point of origin in contrast to "Paul-centered or Peter-centered" is the very same philosophical approach for those who deny the doctrine of eternal punishment. They mount their attack on the basis of the "love of Christ."
This is the same philosophical approach for those who deny the inspiration of the scriptures as they claim that the only real value of the Scriptures is the love of God as expressed in the Sermon on the mount.
This is the same philosophical approach for those who hate "doctrine" but want to emphasize the "love" of God as the only real substance of New Testament Christiantiy.
However, this is not the philosphical approach of Paul as he ALWAYS precedes practical application and exhoration to love one aother with doctrine. He lays a doctrinal foundation first as he does in Romans 1-11 before he makes practical application and exhortations to love. Why? Because "love" must be defined within the context of obedience and obedience must be defined within the context of doctrine.