Yeah. Renovating would be nice. A guild-type thing. Also...the relationship idea, is very creative. Don't think I've seen anyone mention that yet. Jobs would be cool too. Not very strict ones. Just regular jobs. Maybe a swift patrol of a town(There wouldn't always be trouble in the town), guarding a caravan to Point A to Point B, anything like that would be fun. Also, becoming full fledged members of a culture or group...rather than just 1.
I also think it'd be pretty cool to play as a ghoul. A victim of radiation. You'd be looked at, differently throughout gameplay. Shunned.
Also, to make your own weapons from different types of supplies. You could tinker with combining 2, 3, 4 or 5 different items to see what you'd make. There could possibly be 200+ combination results. That would be unique.