Would love to have in-depth NPCs that can be used as hired hands, merchants/traders, quest givers, romantic partners, and children.
Hired Hands:
Whether hired, rescued, or otherwise obtained, it would be nice to have workers that can be assigned tasks to help out, such as tree chopping or guarding. Different than family members.
Merchants / Traders:
NPCs that have specific trades and an inventory that matches their trade. Carpenters sell wood-related items, tailors sell clothes, etc. Can even have an orphanage “merchant” to adopt kids.
Quest Givers:
NPCs that give quests. Could be something as simple as “Do / get this for me, I’ll give you this in exchange.” Possible reputation mechanic.
Romance:
Would love the option to settle down with a player (like my irl partner) or an NPC and raise NPC children. Spouses and children can be given commands like “Follow Me” or “Guard This Area”, or assigned tasks such as “Plant Seeds" or "Hunt Nearby" or "Mine for Ore". Kids might not be able to do much until they hit adult, but they could milk animals or gather eggs or help garden.
Note: If NPCs have can have text chat/responses, the ability to modify or add onto the chat would be cool (for servers or a mod).