Honestly, I think "Amnesia: The Dark Descent" is an interesting game, but overrated. It does as many things wrong as "Dead Space 2" does, just in the opposite direction.
I think the problem is ultimatly that nobody wants to make truely scary games, because being scared is an unpleasant experience, which only certain people can appreciate, and horror has ALWAYS gotten a lot of backlash. I look back to the UK's "Video Nasties" thing in the 1980s as an example (dealing with movies).
As a result they either go entirely in the direction of "cereberal horror", or over the top with ridiculous gore and violence, making it so unbelievable that it's hard to take seriously. It's sort of like how Yahtzee talked about how easily all the models came apart in "Dead Space 2" in his review, that detachment was intentional I think, as making a more... dare I say "Visceral" experience would risk generating criticism of a sort they aren't creating or controlling themselves (like happened with their ad campaign).
Developing a good horror game is going to involve matching the atmosphere, pacing, and psychology with a rewarding, shocking, and fairly realistic (for the fantastic situation) combat system. What's more, someone needs to take a list of things that make people uncomfortable, like satanism, graphic torture, rape, child murder, and similar things and consider that as a checklist of things that should be in such games. You WANT to push people's buttons, that's the entire idea, and why it's horror. There are going to be people offended by any good work of horror, and that's something producers and creators just have to get used to.
I'd be very interested to see what kind of a collaberation between the old "Team Silent" crew and "Bioware" to create a horror themed RPG would turn out like.
While not very successful, Bethesda's "Dark Corners Of The Earth" game was interesting enough where I would like to see them re-visit the genere as well.