I understand your concern the setting (demons, inferno ,etc.) may very well have already been covered quiet some times
But Eurogamer makes it clear that the game is not about originality it's basically a clone of GoWII.
EA has put the dead space team on the job as well as some persons acknowledged for their previous works.
No, it's not about originality, it's about presenting the whole thing in a very ho-hum way. For a GoW-like, the bit with the giant demon was just a let-down. I expected, well, GoWisms, with 'Dante' chopping chunks off the demon, not hitting him once with a scythe and having him dissolve into dust. Maybe I just expected them to showcase some of the main character's personality -- DMC's Dante is very 'cool', Kratos is very angry, while I'm getting more of a NG's Ryu Hayabusa feel from him (the trailer feels similar to NG2's reveal trailer last year, too). Just a blank slate. Which, for NG, as a very technical, skill-based 'action game' is fine. If this game is following the GoW model, though, they really need to make us connect to the main character (we don't have to like him -- Kratos is very unlikeable).
As for the Dead Space team, I haven't played the game, so I'm giving them the benefit of the doubt. They certainly seem like a very technically competent team -- most complaints about Dead Space I've seen were about the by-the-numbers, monster closet gameplay. And that might be a problem with following GoW's mold, which is already a very Michael Bay-blockbuster ninjas-vs-dinosaurs 'add everything that can be cool' game.
And the demons, again, it's not about originality, rather that they look a little wacky and silly when moving. Maybe they're based on actual demons from Doré's illustrations, but they do look like some of the things I've seen in the (much more wacky) screenshots for Brütal Legend.