Confidence easily slips into arrogance at times. That doesn't mean he wasn't a humble and approachable guy one-on-one, but he had an understanding of how things worked that was hard and fast. That isn't to say it wasn't borne of incredible experience.
I happen to be a huge fan of his, and agree with his "school of thought" when opposed to JOC. That doesn't mean I don't recognize that at times in his writing he was arrogant.
There are a lot worse things in the world than being arrogant.
I haven't heard anything you insinuate concerning JOC nor about Keith, so I don't know how either of them were in person. I know the Keith was one of the most experienced in what he wrote, and I have observed that of Brian, and that is what I was suggesting.
