I'm not sure exactly what in your hot take is supposed to preclude the opinion that direction of the film was more artful or that the final product was more gripping than some of his other, comparatively sterile and un-moving, films like The Departed.
Artistry is too subjective. One man's trash is another's treasure. Sometimes directors get too cutesy with artistry and it just detracts from a film instead. Not everything needs some sort of flair. Many movies are better off as straight forward punches to the mouth.
And I also have no idea how you think Scorsese's take "didn't really add anything," when it doubled the moral scope of the film
Yes, it added stuff, but it also had things that I liked more in the original, so overall it didn't really add anything for me. How did it double the moral scope? It passed the buck on some of Cady's immorality to Bowden. And, I don't care as much for the remake Bowden. It adds a sense that maybe he deserves some of it, which in turn detracts a bit from Cady. Bowden is a nice, polite guy in the original. It's more about how much can this nice, calm man take before he pushes back. I find that more interesting, though the movie would have been better served if Bowden ended up killing Cady in the end.
introduced at least two (wife and daughter) unique perspectives
What was unique about them? I don't really remember the wife's perspective nor really care.
and introduced a subplot of the family's adversity and coming back together in response to Cady, instead of having it be a boring family monolith being preyed on by some senselessly evil guy.
The family would have a 'coming back together' moment regardless if they were a dysfunctional family or not. Senselessly evil guy? LOL, the De Niro version is an over-the-top comic book character. You can beat the shit out of him with steel pipes, you can set his head on fire, and you can bash him in the face with a rock, but none of that matters, he keeps coming at you like he's the Terminator. Some problems remakes/sequels make is that they take ideas from the original and then run them into the ground. It seems like Scorsese was so concerned with making it different that he ran some of the ideas into the ground. Did I need an over-the-top, constantly in your face, cheerleader of a villain? No, I prefer the more subtle approach of the original. It seems like some of the stuff Scorsese added was just there to manipulate the audience.
Also, I always liked Robert Mitchum, and everyone likes Gregory Peck, so that's not a knock on the original, but big studio films during that age were certainly constrained in substance. Cape Fear is one of my favorite films of that era, and Scorcese's remake is one of the very few remakes of classic films that I felt gave a fresh, independently satisfying take.
The original pushed the boundaries for its time. As for the remake, I'm not saying it's not worthy. It is a worthy remake, but I prefer pretty much all of Scorsese's other work to it.