Here are some things that I would find to be interesting changes and/or additions to future content (Note: I'm not entirely that far into the game's main story and am only level 17, so I haven't seen all content):
1) Survival difficulty should involve the requirement of eating, drinking, and sleeping (no bathrooming; even avatars need privacy). This seems like a no brainer for a game like this, and on a setting called "Survival". I know some RPG's will have additional options for difficulties that the player can choose to incorporate, so maybe this could be one of them.
2) Another thing with difficulty: instead of health bloating enemies (I know plenty of people have griped aobut this), I wonder if there could be one or both of the following: a) increase the number of enemies that spawn (which would be nice regardless) and/or; make experience gain slower. I've read some discussions about changing damage output for both the player and enemies, but I'm not going to try to comment on that.
3) A good idea I saw someone else post was the introduction of caravan missions; something along the lines of protecting the caravan as it travels from settlement to settlement.
4) And on that note, protection missions in general would be pretty cool. I realize there are opportunities to defend your settlements, but the one time that that happened for me, I didn't even realize I was being called on until the mission failed. Another idea would be defending key strategic points for factions; maybe some intel comes through about a roving band of super mutants and you're asked to go defend a particular town or area.
5) Add missions where the player is asked specifically to resolve a conflict peacefully.
6) Add experience for successfully using the sneak skill around enemies.
7) Add the ability to do mercenary work.
That's all that's really coming to mind right now. I could go on about areas that need improvement, but I'm sure they're aware of the issues that are being called out about.