I always look at these things from a "What can mods do to/with/for this feature" perspective.
Though I'm sure there will be limitations on how your personal colony interacts with the rest of the NPC world, I'm certain folks will add content that allows for peeps to rehabilitate some areas to their former full pre-war splendor (defended by automatic guns, trained deathclaws on leashes, and other such ... because raiders).
If it isn't as restrictive as Hearthfire in Skyrim, only allowing us to design and build inside a certain footprint and style for each area, then, we could potentially see folks building their very own personal Tenpenny towers and/or other more fanciful things.
If BSG has Minecraft'd the base building aspect, and we have the flexibility to build things brick by brick, it's pretty certain all sorts of [censored] fun from those of us with a touch or more of OCD will get gotten up to.
No doubt, someone will build a 1:1 scale USS Enterprise, or a Deathstar, or something else if the flexibility is there.
If that flexibility isn't there Vanilla, and it doesn't take much to add in some brick by brick building ability, yeah, we'll see some Taj Mahal stuff happening.
As far as industry and trade with the rest of the NPC universe available, if it isn't there Vanilla, bug the people building the USS Enterprise or the Deathstar in the game to expand on the industry and trade aspects through the mod tools, and it'll soon see the light of day.