I'm sure this is not a new idea, but have you ever considered a SIMS style strategy for Fallout? Basically an expansion of Fallout Shelter, keeping the focus on developing a vault from scratch, keeping people happy and productive just more in depth? Being able to explore the outside world more, protect against attacks, make relationship with groups outside the vaults, etc.?
Could have a single player campaign deal and a multiplayer....different player vaults able to interact with each other.
Again I'm sure this is not the first time this has been mentioned. With the success if Fallout Shelter, I was just curious if this is an idea fans might consider..