the game tracks wind flow direction.
Then add a way for mobs(animal) to be able to track by smell to the animal AI. This could tie into the rest of the OP. If the animal is the type that runs then as soon as it smell you it will start moving away from you. If it's the fighter type then it starts to move to you. This could help make hunting more like hunting as in you only head into the wind when hunting. There would have to be a way for us to track wind as well, So that you knew what direction the wind flow was headed.

Maybe add the smell tracking to upper skill level hunters. Telling you "you smell a XXX", Letting you know what type of animal is up wind from you.