Bultmann got a lot of things wrong. But he got a lot right, too. As I've been reading him for the first time in any sustained way in recent days, I find his understanding of Paul much more satisfying than Sanders, Dunn, and co. For example:
The attitude of sinful self-reliance finds its extreme expression in man’s ‘boasting.’ It is characteristic both of the Jew, who boasts of God and the Torah (Rom. 2:17, 23), and of the Greek, who boasts of his wisdom (1 Cor. 1:19-31). It is also a natural tendency of man in general to compare himself with others in order to have his ‘boast’ thereby (Gal. 6:4).
--New Testament Theology, 1:242
Yes: there is a universal human tendency toward moral self-establishment of which Sanders appears to be completely ignorant, as much as he has helped us all in putting away once and for all a distorted, one-sided view of Early Judaism.