Either in the form of a Hardcore difficulty or better yet Hardcore settings that can be turned on/off anytime or at the beginning of a New game would really touch my Survival hole. Hell, alternatively if the Map editor gets complex enough, I'd love to see them allow the community to create their own gametypes, co-op/competitive missions, etc. which would allow fans to make their own survival/battleroyale/fishing sim and share with the rest of the community.
Pipe dreamin baby!