Doom 3 was utter shit, I don't see how they could possibly screw up 4 even more. Doom to me was always about slaughtering hordes of demons with good special effects and level design.
Yeah, it's a huge shift from Diablo 1, but as I mentioned earlier the genre just isn't suited for horror. Diablo 1's gameplay was pretty terrible. I don't blame blizzard for subjugating the art to service the gameplay.
Not suited for horror?
Sure, it's suited for horror, but no developer seems to have any interest in pulling it off.
If you have ever played Sanitarium, it was very effective for being an isometric horror-themed adventure game.
A newer isometric horror game would be Stasis.
Shit, if the team behind Hellgate London would have delivered, we would not be having this conversation right now.
All/Every RPG is fantasy that is one way or another ripped-off from LOTR.