Surprised this isn't a mechanic yet.
You should be able to catch diseases from animals and other players, ranging from minor to life-threatening. Would add more variety/challenge to the game IMO
Imagine there's word of an epidemic in X realm. Now villages in other realms have to be extra careful when vetting applicants from that realm to ensure they won't bring the plague with them
This could also make the hunter/herder experience more challenging since now you have to check if an animal looks healthy or not before killing/processing them
We'd probably also have to get more medicines and other medical items added to the game (masks?). I feel right now medicine is sorely underdeveloped