Well sayed, and also great explanation in video.
That was a good idea to insist on this point. Well done sir =)
But you may also notice that creating a good custom story take time, serious interest, imagination to create a story, and mostly skills in level editing and scripting, and this might be the real problem. Also that's only my point of view.
I didnt read everything in that thread so maybe it's already sayed, but the way used to create a story in a game is also the same for a movie. So if you have no idea for a story, then just watch some horrors movies