Should this be on the list of top 10 all time best horror movies?
I think it should.
It's not just a great horror movie, it's a great movie. It's touching and makes you think. The horror is both supernatural and completely real. How many horror movies dare to overlap like that?
The acting is superb.
One reason why it may not make the list, is that it's a rare horror movie that has No core villains in it. It's not Silence of the Lambs. There's no villain with more than a few lines of dialogue. Pretty much all horror movies have a central villain. Silence of the Lambs for example. But also popular horror, like Jason, Freddy, Chucky.