Who gets it wrong? Barth or McGrath? Aide moi!

I don't claim to be a scholar of Barth, so any help from experts would be appreciated. I have just read an article by Alister McGrath on Karl Barth's doctrine of justification in which he argues:

“Whereas for Luther, the gospel was primarily concerned with the promise of the forgiveness of sins to sinful humanity, for Barth it is primarily concerned with the possibility of the right knowledge of God” (McGrath).

My problem with this criticism is that it underestimates the topics of sin and forgiveness inherent in Barth's understanding of the knowledge of God. Of course, key to this discussion will be CD II/1, and especially § 25. There, Barth explicates the knowledge of God in terms of faith and obedience, love and the fear of the Lord. Reading this, it seems highly dubious to me to isolate the knowledge of God, in Barth, from forgiveness and sinfulness. Epistemology, in Barth, is not simply cognitive, but embraces the whole of life. So Barth’s paragraph heading for this section runs:

“The knowledge of God occurs in the fulfilment of the revelation of His Word by the Holy Spirit, and therefore in the reality and with the necessity of faith and its obedience. Its content is the existence of Him whom we must fear above all things because we may love Him above all things”