The team totally collapsed and gave up on Matt in 2015. He was way in over his head. Had no idea how to handle the Papelbon acquisition and Storen.
In any event I figure a really good manager is worth a couple games a year and maybe one in the playoffs. To much emphasis on the manager and not enough on the players IMHO.
While this is generally true, I think there's a reason Dusty Baker has never won a World Series despite being at the helm of a great many talented teams.