"For example, wouldn't a Bishop need extra grace to go through life in celibacy?"
Absolutely. He receives grace at his monastic tonsure (which would give grace to maintain the struggle of celibacy), and at his consecration to being a bishop (which would give grace to live that celibacy out in the world -- bishops are the only monastics who by definition are charged with living out their monastic life in the world.) God gives grace through these sacramental acts.
My son recently made an interesting remark to me when we were discussing the preaching of various Orthodox clergy that we have known over the years. He observed that there was something different about the preaching of bishops -- that it seemed to be more powerful and penetrating, even if the bishop wasn't a particularly "gifted" preacher by "objective standards."
I pointed out to him that it was not his imagination, and that this was not a result of the psychological effect of us seeing his special vestments and knowing that he is a bishop.
In the Orthodox Church, only bishops are specifically charged in their consecration to preach and teach the faith. Preaching is not, as far as I know, even mentioned in the ordination services of priests and deacons. When a priest preaches, it is through the blessing of the bishop who can't be there every Sunday. Bishops receive a special grace to preach, and the presence of that grace is usually unmistakable.
My son didn't know about the particular relationship between preaching and bishops, and yet he had zeroed in on it through observation.
That's interesting, I didn't know that. So a full bishop is normally the one to conduct services? I suppose I had always assumed something very different, that priests handled the day-to-day operations of a church, including preaching, and that bishops were more in an administrative role. I may want to check on one thing with you to make sure I'm thinking of the right thing. By "preaching" do you basically mean saying the homily? My understanding is that a homily is akin to a sermon.