One scene that I feel is not overkill and should have never been deleted in the first place is the scene when Sonny goes to his father's office after The Don is shot. Watch very closely and you will see that Sonny just can't seem to bring himself to sit in his father's chair behind the desk.

As Mark correctly pointed out in one of his other posts " this was such a little thing that spoke so loudly"

While there is no actual dialogue in that scene, it still speaks volumes!