I think it's just that it's been so, so long since a horror movie has even remotely entertained me, that I really would love to be genuinely surprised or outright disturbed by whatever completely alien situation Shyamalan might throw on screen. I mean, what's been scary to me, and most people I figure, is the unexplainable - forces which could potentially exist (i.e. none of this unbeatable demon magic bullshit), yet play by a completely different set of rules that aren't immediately apparent, that the cast has to grapple with and figure out.
I loved stuff like Cloverfield, Dawn of the Dead, most of War of the Worlds, and even fucking Signs because although in most cases you could piece the overall story together, a lot of it was the cast being shaken out of complacency, having to adapt and survive in the face of something which, as far as they knew, they weren't very likely to fully understand. Shyamalan's a bad director, The Happening kinda forced me to face that, but at least he seemed to of been, well, trying to actually scare me.