I don't know if I'd say he took over a veteran group (DeAndre and Boat had only played two seasons between them at that point, both of which were fractured for different reasons), but I take your point. It was a team of self-driven guys, most of whom had played for Calhoun. I still give Ollie a lot of credit for that championship as well, but it's fair to say he's unproven at running a program in all aspects.
With Mullin, there might be some ancillary evidence that his current trajectory is unsustainable, but the trajectory still is what it is and I'm willing to keep an open mind on him until he proves incapable of managing actual talent. The victories over Duke and Nova last year bought him at least another season, even if the retention issues you mentioned need to be resolved.