I don't think this will help, but the reason why I love this movie - giving it a 10/10 rating - is because of the following reasons:
1. The stunning tension, there are brilliant scenes that stunned my cousins and I because of the tension. i.e. when Marcus was sitting and playing the piano the Lullaby starts playing nearby. (We were literally holding our breaths). It was established in the previous scenes that it is the murderer's calling card. That was so creepy.
2. The cinematography, which honestly a lot of directors have imitated (John Carpenter is one of them). For example Tarantino often takes long, uncut scenes like Argento did with Deep Red. Especially in the Director's Cut the cinematography is really well done.
3. The script. Yes, the story has its absurdities (the medium, the doll, the wall hiding the body etc), but each scene is carefully staged and it would not be the case if not for the solid script.
4. The atmosphere, it is paranoia inducing and keeps you at its grip long after the movie has ended. I sometimes start looking out the window to see if someone's watching me after I have seen the movie.
5. The music, it was important that the right music was used to set the mood. I think it was very fitting to use Goblin's music. Jazzy, gothic but still Baroque enough to give the movie a brooding, if not, creepy atmosphere.
I am not expecting you to see it the same way I do, but that is why I love the movie.
P.S. Saying it is the most boring horror movie ever just because you find it boring, is a logical fallacy. A) I find it boring, so B) It is the most boring movie ever, because of A).