Why would anyone want to live in vault if they have a nice town on ground. It's just a glorified basement.
As far as I remember in F2 it was used as storage space and that actually made sense.
How much time do players spend in their bases or tents? Most time spend in fixes locations, as i observed. So why not make this more comfortable and even symbolic. I think that most people associates Fallout with Vaults, Power Armors, Brahmins
, Harold and other typical symbols. So Vault as a main base is not anything against Fonline nature.
It could not be a hi-tech vault. Look at Lexx's vault base (i think he create that map). I like how he created. Abandon or unfinished shelter style, decent design. But this base, although is most expensive, is most useless. Ergonomy is one thing. Second is location. Third is that even you collect and buy this base it is not at the start of existance of your faction. So you buy it, but never ever move there all or majority of stuff you have already collected and stored at first base ground.
So for me, it is wasted potential of good created and atmospheric map. So i would rather see it removed from bases maps and make i.e. dungeon from that map.
Or make it as a first base map. Instead of buying new and new bases (for settler players), you will be focused on upgrading => workbench, elevator, car garage, water pump, brahmin pen... It would be nice to be able to upgrade it and maintain it by random, craften, traded, special event gathered items. And of course, you would be still able to buy other bases for your local needs.
And JovankaB, you are right. People should be more in cities. But dont you think, that gathering upgrades and maintaining items from cities could help eliminate empty city state?