I think coaches have become too specialist. They earn the big dollars and are the focal point at the football club but a lot of them seem to have narrowed their role to just football strategy. Game plan, match day moves and whatnot.
What should have happened over the past decade is that the football manager should have become the main person in the club. They should be the obsessive micro manager, across every detail of the football operations, with good knowledge in fitness, development, tactics, planning, boot studying, skills development and so on.
They should be getting the big dollars at the football club. They should be the person who is highly sort after. The person who gets sacked when things aren't working. Someone with a great experience and knowledge of all aspects of preparing a team for a game of football.
The actual coach would just need good relationship with the players, get them revved up, get them all on the same page and pulling in the same direction and give the instructions on match day.