How did you feel about A Machine for Pigs? I felt the real story there was the way the father went crazy, and the role the church had, two really believable plot points. Not really the man/beast moster and so on which was less believable.
I do agree though, for what it's worth they have two projects in development right now so maybe one of them is more scifi.
I also think that Amnesia: TDD was Frictional's weakest game (not bad but just not as good as the others), in particular due to the more mystical "ancient alien" plot.
Personally I prefer A Machine for Pigs over TDD for that reason too but I was always under the impression that it was mostly The Chinese Room's creation and that Frictional's involvement was limited to the more technical and publishing aspects.
I do agree though, for what it's worth they have two projects in development right now so maybe one of them is more scifi.