I think usage patterns matter, how you sequence guys and how you schedule their work. Unless one of them happens to talk about it in some interview I guess we aren't likely to know how Fetter and Hinch split up planning those aspects other than being familiar enough with Hinch's managing in Houston to recognize whether he is doing things differently with Fetter on board.
I think it's possible for a manager to have a lot of insidious bad effects - particularly on young hitters, if he pushes them into or makes their playing time contingent on taking approaches that don't work for them. Again I don't know any a fan would ever know - at least not until long after the fact of a player leaving and going public with his grievances, which you can't necessarily believe either. And of course what an activst manager does might also work for a lot of guys. But that is the downside risk I worry about with a guy like Hinch who clearly has a more "interventionsist" kind of mindset around the how and what he want his hitters to be doing than for instance Jim Leyland ever showed.