I remember when Ryan Block left Engadget and people were saying similar things, wondering about Engadget's future. Josh eventually grew into the role and now he's leaving. While it's sad to see him go, I'm sure someone else will eventually fill the spotlight.
But did three of the top contributors leave with him? I think the fear is that both Miller's, Nilay and Josh left within a few months. Usually when you have an exodus by senior staff that isn't a good sign. Plus their posts are getting more and more snarky ala Gizmodo which is why I don't read Giz.