OK, I can think of one other instance where voice-over works...if you create a dual-protagonist.
Think Ishmael and Captain Ahab in Moby Dick, or Andy and Red in the Shawshank Redemption.
If Moby Dick was written entirely in 3rd person about Captain Ahab, it would be a story of high adventure on the open seas. About a guy chasing a whale and seeking revenge. Still a good story, but simpler than it is. But because Melville told the story through Ishmael, all of that is included, but now the story becomes deeper, a story about not just revenge, but about survival against the backdrop of monomaniacal revenge. Ishmael and Ahab are dual protagonists, in it together (along with the rest of the crew) seeking out the white whale, but in the end the conflict centers around one protagonists survival vs. the other's death.
Now, let's translate this to a film example. The Shawshank Redemption.
If the story were only told in 3rd person, that is following Andy around with the camera and no narration by Morgan Freeman, the story would still be good, but it would simply be about a man trying to break out of prison. Even if he's wrongly there, the story would be about a man trying to regain his freedom. Still a good movie, but different than what it is. Via Red's narration, Red and Andy become dual-protagonists. Sure, Red is a mentor to Andy in Act II, but both are trying to survive and live through prison life. They both have the same dramatic need in Act II, and are therefore dual-protagonists. But since they see their world in two completely different lights...that is what makes the narration and the story richer. Andy is full of hope. Red tells him hope is a dangerous thing and he better forget about it. It's the contrast that makes the voiceover work.
We see two different things on the screen and in the voiceover. On the screen, both characters have the same dramatic need, but the action follows Andy as he explores prison life, takes command of his life in prison, and ultimately escapes. But the voiceover tells another story entirely--cynical Red changing into a man who has hope by the end of the story. And Andy gave him that hope.
So I guess I can say that when you see voiceover work in story, it's probably because the action and the voiceover tell two different stories. That's my conclusion.