The horror element wasn't removed, it's just our mindset is already prepared and know what to expect for a 3rd time, Necromorphs jumping out of the vents, stuff possibly jumping down behind you etc, once you get use to things it's not new anymore.
Too many action cut scenes with huge explosions, the enemy didn't even try and be sneaky or go for the shock factor of making you jump. I jumped a bit sometimes in the earlier games when supposedly dead enemies would leap to life when you walked over them. They make annoying noises that might have been scary hearing it a little bit in the distance, but no they constantly make the noise while they slowly jog towards you. I never once came anywhere near running out of ammo, the fact that ammo is universal now made sure of that. And I ran around never with fewer than 10 health packs at all times. All element of danger or fear was removed because in EAs books, generic shooters with explosions sell well completely ignoring the fact that people don't buy Dead Space for that experience.
I still remember stumbling around with close to zero health in Dead Space 1, dreading encountering an enemy because I only had 2 shots. The atmosphere was incredible.