You think Rocco is in the bullpen teaching pitchers a new pitch?
You think he's in the batting cage, going over film on how to help Julien get out of his slump?
Maybe Kelly did 35 years ago - but in today's baseball world - thats what assistant coaches are for.
Today - the managers are like the GM of a business. They are ultimately responsible for the efforts of the team, and IMO, get too much credit, and too much blame when things to great or poorly. But it is the assistant and position coaches who are responsible for player development. In Rocco's case - he didn't even get to select who his position coaches were. In fact - I don't even believe the coaches the FO selected were given the ability to coach the way they thought was best for the team. Instead - I really think the FO selected the coaches, and then told them how to coach. Just look at the success of Popkins before and after leaving the Twins.
So sure - back in the day, Kelly was out there in his Zubas teaching the fundamentals to the 3rd baseman - I just don't think thats how it works in 2025. The Manager.... manages (what this FO will let him manage). The hitting coaches develop (or don't develop) the hitters, and the pitching coaches develop (or don't develop) the pitchers.
If we have poor player development (we do) I believe this is on the FO because they are the ones selecting who develops the players.
I feel very confident saying that nothing will change with a new manager - as long as the FO is selecting the position coaches, and possibly telling them how to coach - nothing will change.