Paul was a great theologian. A theologian is someone who sees problems where nobody else sees problems, and who sees no problems where everyone else sees problems.
An interesting video of a Krister Stendahl Lecture being read by his son. Krister Stendahl was, according to Wikipedia’s article on the New Perspective on Paul, one of the guys who got the “New Perspective” going.
Something that emerges in this video is that keeping Paul but minimizing his doctrine (and everyone who keeps him must minimize some of his doctrine since he is so contradictory) ultimately leads to a sort of subjectivism: “Christianity is true for me, but not for everyone.” It becomes clear, therefore, that a rejection of Paul is essential for Christianity to maintain itself (or rather, Jesus) as the truth, not just “a truth.”