Board Thread:Warhammer 40k General Discussion/@comment-26165786-20150304163255/@comment-6078851-20150418150134

the whole doctrine of the dark angels, which came from the knights of caliban, probably worked against jonson's public image as it fostered a lot of secrecy, and as mentioned he was, like the dark angels themselves, somewhat reclusive.

but while many people may not have recognised jonson's abilities, his brothers and father did: alongside guilliman and horus jonson was one of the few genuine candidates for warmaster. jonson was considered the best strategist amongst the primarchs, or at the very least tied best with guilliman. horus was a great strategist too but not the same calibre as these two, but what he lacked in this regard he more than made up for in charisma and 'people skills', and the lack of these is what ultimately ruled out jonson and guilliman. although in terms of people skills jonson was severely lacking, which is understandable when your childhood is spent in an environment where everything is trying to eat you :P