I don't get the hate for Barney. In a good lineup, you bat him 8th and eat the low average for occassional clutch hits and gold glove defense. He's young, cost-controlled, and provides a defensive highlight almost every game.
Not everyone in the lineup moving forward will hit .300 and be an RBI machine. There is a premium value for elite defense and I think the people who believe Barney is expendable are greatly under-valuing him.
You just described the type of player every team needs, but that in and of itself doesn't make said player part of the "core". I would say that type of player is much closer to being part of the "crust".