In most MMOs NPCs serve as nothing besides cannon fodder or quest givers. I believe they can be so much more in Crowfall. They should effect the gameplay and be more than just sacks of XP for players to kick around.
In gameplay players should be able to use NPCs as soldiers/militia and order them around in combat. This would create huge battles even if there were only a few players playing at that time. This would also allow players to use tactics like flanking or ambushing in combat instead of just charging in head first.
Another reason why there should be more intimate NPC combat is it would open up the ability to train NPCs to be better soldiers thus creating value in NPCs and giving NPCs a fighting chance when they have to face players in combat. This training could be done through winning/surviving battles or being trained by the player or at a training building.
Players who own land could send these soldiers on patrol or order them to raid or guard land or guard a caravans thus giving players more versatility in their gameplay because would be able to do several things at once without having to be spread incredibly thin.
(This could also added to the mercenary system that is on another suggestion page)
Another idea is that these soldiers or any NPC lost in battle would not respawn thus giving weight to the deaths of NPCs because ti cot time, money, and effort train them and now that they are gone you have to do it all over again and while you are training another NPC you will be down a soldier.
I never liked in Sim City that "oh great an earthquake just destroyed everything I built up" However, I'm a big fan of dynamic events so I could envision some form of natural disaster event that didn't occur within x radius of a player controlled fortification.
It's one of those things I've thought about on and off since I started working on Crowfall. Still just a personal mind bubble for now, though.