@rotated It's probably an error to think that there's any real template for success. It's more about the individual. Measuring success by winning World Cups, every one of our pro era Head Coaches had a failure - Henry and Hansen also won one.
After 2011, we've been sold a continuity template - and there's plenty to be said for not throwing the baby out with the bathwater - but, you still need to look at the individual. Continuity didn't work in 2019 and my jury at least is far from convinced about Fozzie.
Perhaps another point that shouldn't be missed is that the ex-players who are coming through now are sort of a second generation of pro player coaches. Guys who spent most of their professional playing careers in proper professional environments.
So I'd differentiate them from e.g. someone like Jeff Wilson who tinkered a bit, and a bit unsuccessfully, with coaching - but played 1992-2002, but even in his pro-era playing days was probably in environments where mainly the coaches were still feeling their way and learning what pro coaching was all about.
Edit: Clive Woodward can be added to Rassie.