would say the biggest threats to real christianity are internal, in that we have many of us saved, but 'fans" not disciples of Christ, as we have right doctrines but does not show up in how we live our lives, and that we allow for aberrant/heretical theology from likes of WoF, and that we have also denied the reality of Sin and the Cross, having remade salvation as doing and saying right thigs, as all basically still 'good"...
In the article you referred to the author gives a brief definition of the gospel, and then compares 6 counterfeit views of the gospel. His assessment of 6 counterfeits may be valid, but I find difficulty with his own summary of the gospel. Here is his definition of the gospel:
This definition of the gospel is different to my understanding. I believe that Jesus’ death was representative and not as a substitute Romans 6:1-8, Galatians 2:20. I also believe that the principal aspect of the Kingdom of God is the Kingdom that Jesus will establish when he returns to set up his kingdom upon the earth and reign from Jerusalem Psalm 72, Isaiah 2:1-4, Daniel 2:35,44, Acts 3:19-21, 8:5,12.