Fear, Hope and Dread
If I were to ask you what the most important element of the primal emotion "fear" was, what might you say? The best answer would usually be not knowing, a lack of understanding. And while this is true, there is another factor that is second most important to fear, and the one that we as players can control more than any other: Hope.
Now, before I get into hope and dread, along with how us as players can actually affect it, I must first talk about the "Fear of the Unknown". The single most important part of all horror. The human imagination is a very complex and self-detrimental thing, and when left to its own devices, it goes into the worst possible scenarios. To save time, I will just say this: When I started DbD, the Terror Radius sent me into a panic, as a now Red ranked survivor, the scariest games of DbD are the ones where two generators have gone, it's been 3 minutes and I haven't caught a single glance at who the killer is. I have no idea and I do not know how to face them. My mind is racing through all the possibilities and can't decide. Paranoia and fear of the unknown as set in.
This to me is part of the joy of playing a Stealth killer. And also being an unseen predator, like a lioness in tall grass. Unfortunately all of the stealth killers are hampered by mobility, and if you dare say "BUH WRAITH!" then just no. His bell cancels out that point.
Hope. Terrible perk, don't run it.
Hope is a very powerful force for the human psyche that allows us to try and persevere through some of the toughest situations, as the possibility of a positive outcome leads to a desire to achieve this outcome and action. Within a round of DbD, it is hope that drives us to take action within the round. It's why survivors run to pallets, hide in lockers, bodyblock for others or even wait until the last second to get that generator done. It is the very thing that keeps players going, clinging to the chance that they can escape the trial.
Without hope, what do we have though? We have dread. There is no chance of escape, of survival, so what is the point of continuing? Why should I remain in this trial? Why should I continue to play the game, if I'm never going to have a chance of "success"? It is possibly the biggest contributing factor to hook-suicides. Without hope, there is no real trial. Only a mindless slaughter.
For me, for there to be fear there must be an element of hope. And for that, I have seen no better moment than in the series Fate/Zero when the servant known as Caster is summoned. If you've seen it, you know. Another that you all may be more familiar with is the myriad of traps within the SAW franchise, and how the test subjects frantically go about trying to get out of their situation. There is a CHANCE that they can escape, and there is tension that rises from the hope that they hay escape.
Now, I know that this is a long post and that mine usually are. But just some food for thought to make DbD more of a horror game again: Sometimes giving survivors that little bit of hope goes a long way. Not just because they like you more and are more likely to stick around and continue playing the game, but because it is WAY more fun to see the lights in their eyes get snuffed out as they're moments away from safety.
And while I am normally against tunnelling and camping because they feel terrible for me as a player to both do and be on the receiving end of, just consider that all it creates is dread and despair. The antithesis of what a horror setting tries to accomplish. Sometimes if you give an inch, they'll take a mile, but others it will lure them into a false sense of security.
Use that Ebony Mori, but wait until they're on death-hook or even wait until after someone has died through a hook sacrifice. Let them make that dangerous save in your face, but trade them out and give chase for two seconds before going for the hook. Take a chance with a hatch escape from time to time, rather than slugging when there's two left. Trust me, it'll make things more interesting. For both sides.