Personally, I think it would be cool to see more mods (or even updates) that give you more side things to do on your downtime. Right now, the game gives you a lot of opportunities to explore the map, find easter eggs, do whatever, but what if I want more stuff to do at the base?
I couldn't really give a whole lot of creative ideas, but the universal mods tend to be, being able to watch YouTube or streams on TV, or some more radical mods, like being able to play emulated games, which is wild.
Though, I would like to see stuff that could feel official, too. Exactly what? I'm unsure. Heck, I'd even settle for adding more food types and cooking recipes to the game. That could totally be official.