Seasons and Weather.
So that we have to develop a Calendar of sorts? Store food for times when we cant farm. Craft Ski's or snow shoes to cross Wintery snowy terrain. Cold hurts you after a time if you arent wearing fur or warm clothing...
Stuff like this. (Your waterskin freezes too long in the cold) but can be warmed by a fire. So if you get caught in the cold your water might be unavailable.
Food Decay and Spoilage (I know this has been said before but I'm throwing it back out there) >>> Seeing as we now have salt in the game!
- Add "Smoked Meat" Recipes for preservation, and other preservation methods (such as the granary idea)