Man management seems to be a big thing. A lot of coaches have talked about it being the biggest part of the job, and the strategy/technical stuff being something that can be delegated to assistants. I played with several guys who had been in the Broncos system, and they all said that Bennett was always really up front and honest with every player - even if/when he had to let them go. They all loved him for that.
John Cooper - one of the most successful current pro coaches in North American sport - says that he has built several successful teams with the mindset "culture over x's and o's". He says that while the technical details of how they play is important, they won't win unless they like and respect the coach, like and respect each other, and enjoy coming to training/games.
To a certain extent some of this can be delegated/offloaded. I know that at the Broncos currently it is Ben Ikin's job to built the roster, and he is big in to analytics around getting the right mix of youth/experience/strike players/steady players and so on. Ultimately this is done with oversight and/or heavy involvement from the head coach, so it's up to Kevvie to make it work once Ikin's given him the players.
Ikin says that he signed Ryan James for culture reasons, and he says that as soon as Xavier Willison (dev player currently recovering from ACL injury) is healthy he will be in the squad - even if he may not be 100% ready for NRL. Apparently Willison's work ethic is a cut above the rest of the young players and having him set the standard will push the rest.