Q. Please explain what you mean about the two extremes in Christianity,the dead orthodoxy of mainline Protestantism, and the zeal without knowledge Charismatics?
A. In John 4:24 Jesus said, “God is spirit, and his worshipers must worship in spirit and in truth.” In their determination to escape the false doctrine of Catholicism, the leaders of the reformation chanted “Sola Scriptura”! Only the scriptures. They developed the great seminaries to study and understand God’s word and to prepare pastors to preach it. As time passed it became more and more of an intellectual pursuit and as it did the inspiration of the Holy Spirit became less evident until in their intellectualism they were denying the inspiration of Scripture, the deity of Jesus, the possibility of miracles, the need to be born again and the validity of predictive prophecy. In their search for the truth, they lost the Spirit.
The Charismatic Church sprang out of Pentecostalism and was an almost anti-intellectual movement. As believers fled the main line churches, those with the greatest zeal and passion for the Lord became the teachers and pastors. Lacking the grounding that comes from years of preparation, they often lacked discernment as well. If it appeared to be a working of the spirit it had to be good whether the Bible mentioned it or not.
Like the Corinthian Church they gave extra credence to the sign gifts, tongues, prophecy, and the like. Supernatural experiences overtook the study of the Word in importance and theirs became an experiential movement, needing the latest spiritual fad to sustain itself. New things like a special baptism in the Holy Spirit, prayer languages, holy laughter, and the like that never appeared in the apostolic era became commonplace and they grasped onto them with great zeal, never confirming them with scripture, as Luke advised us to do in Acts 17:11. In their search for the Spirit they lost the Truth.
Of course, all of this is a massive over-generalization. There are many good, Biblically sound fellowships in both movements. But you asked for an explanation of the extremes and you got it.