Interesting review. Of course, I think I love this film considerably more than you do! So I'd give it 3.5 stars. Some comments--
Regarding Granger's character...he's obsessed with his heritage, his right to belong to the society that surrounds him but ultimately rejects him. His obsession, like Heathcliff's is what drives the film (as well as her needing to belong in a stable environment). They have that much in common, and I think you touched on some of this.
I don't think the film did as well as they hoped, because it's a little too deep for audiences that want a soft melodrama. But it's the profound nature of the story that resonates with me most. We get this sequence in the beginning where she is dying while giving birth but we don't really know it all nor do we know the circumstances because it soon cuts to a flashback. After the entire story is told and we return to the birthing scene, we are given more than her death and her passage beyond this life. We are shown a great irony, namely that she has named the son after Granger's character, so in a dramatic turn of events, a Phillip Thorn (the next Phillip Thorn) does inherit the estate.
Allegret's ending is shocking, because we are reeling at participating in her death with her, then we get this knowledge that the so-called circle of life has been completed and the Fury estate (not the Blanche estate) and Phillip Thorn are forever connected.
Going back, for a moment, to your comments on the final act of the narrative-- she has a major change of heart. She turns him in, because she realizes that the murders were wrong and that because she is now pregnant (which is revealed at the trial), she has to make sure the sins of the father are cleansed before the son is born. As I said, there is a lot happening in this film and the visuals are in a way deceptive, because we have the trappings of a decadent Victorian lifestyle, but we also have some naked truths about these characters and their intertwined destinies.
One thing that I thought was absolutely brilliant the way the story was structured is that the gypsies bring them together in the beginning (retrieving the horses) but the gypsies and the hoax surrounding the murders, is also what tears them apart. So we have a great example of the subplot conveying the deeper themes and having a direct affect on the main plot. And speaking of the horse, the scene of the girl dying reminded me a lot of the one in GONE WITH THE WIND.