Would like to see Barker as a senior coach with strong assistants somewhere else. I think it could be successful. Good motivatot, loved by the players who would buy in and play for him. From the outside he lacks the specific technical knowledge that top assistant coaches have but has all of the qualities the senior coach needs.
I saw this once in a high class restaurant- assistance chef couldn’t cook to save himself- but somehow when he came to run the kitchen as executive chef it ran like clockwork.