With how there was already a settlers mod in the past two Fallout games, I think modders could add even more items for bases and settlements that Bethesda might not add. I hope we get the ability to make our own vault(s.)
We will see. As they say time will tell. It will certainly be interesting to what the modders can bring to the game to keep it going for longer and longer!
I also hope they -include- killable children this time. Yes, don't let us kill people vital to a quest unless that's an intended option in said quest, but .. to make all kids immortal is just so annoyingly unrealistic. And the worst part is, it turns people against you, even though nothing happened at all.
I do love how the game is so gorgeous and seamless, where you can start a conversation with someone and then BAM! Shoot them mid-sentence or just walk away.
They probably wont include killable kiddies. As that would instantly pull a major neg attention to themselfs. A mod will probabaly come out for that tho.