Single player content.
First off let me start off saying yes i know the game is online only. Yes i know there is most likely never going to happen. And these are my own opinions and thoughts and if you disagree with them fine, just don't be a d**k about it.
I found out about this game like 1/2 a year ago, and i enjoy it...for the most part. I've never been a fan of online only games but I gave DBD a chance and I have fun but I honestly feel in my personal opinion that the game could use some single player offline content. I know in one of the streams they said they couldn't do it, but lets be honest you can do it, you just don't want to. And the game can have some form of single player content, like Chapter stories where you can choose form either killer or survivor from that chapter. Like for example the Saw chapter they can have a beginning cutscene that leads into a mission/ challenge then continues from there. They can have cutscenes like how they do for the trailers, like the most recent one the Curtain Call trailer shows how a survivor or killer missions can start off, then it leads into another cutscene.
So finally I know this is never happen but i feel that DBD could have a cool story offline content and I know some people who hate online only games and would buy this game if they ever released one.