Kevin Long is the only one I think we'll miss.
But its Davey's team now. He gets to pick his staff. I just hope he can bring in a decent pitching coach.
I really don't think managers matter, and I think assistants matter even less. I hate to say it, but I think the most important attribute of a pitching or hitting coach is the ability to be fired and get the player's attention.
I think they only matter to an extent they keep the clubhouse together. I think Matt Williams was fine, but lost the clubhouse. Dusty Baker came into the place, fixed the clubhouse, had a great few seasons. Davey Martinez seems fine for simple fact he runs the clubhouse well.
Baseball decisions are so statistically driven now, and with the 3 batter minimum and universal DH, even less for a manager to do. There are still pitch to pitch decisions and some managing, but I believe the most important thing is keeping guys motivated day-to-day to work to improve their craft.