Bizarre, just bizarre thinking.
IIRC we've agreed that Mookie gets to balls that JBJ would get to, thereby reducing JBJ's chances and deflating his dWAR. Then we talk about getting rid of JBJ not knowing if Mookie will be back. Whaaaaa?
But you're right when you say that, "the focus might shift from expensive elite defense towards significantly cheaper adequate defense." It might not, too, and given DD's propensity for liking solid defensive players (remember, he tried to trade for JBJ when he was in Detroit) I'd be surprised if it happened. DD's no idiot.