I would love to see night time in game have a sense of danger when you stray from the beaten path and add some fear of the dark.

Much like Terraria, Minecraft, XI and other games, let loose the undead during the dark hours.
Would love to see Zombies stumble around, Skeletons rise from the earth as well as ghosts, bats and demonic spirits floating around in the darkness of the night.

Of course keep the captiral cities and surrounding low leve areas safe at night, but the further you get away from civilization you get the more chance you walk upon haunted grounds.

Least for me this would add to giving a feeling of excitement when traveling far out (will i make it there in time before night falls?), making it more of an adventure when exploring further reaches of the maps or when walking to far away camps.

Would also realy like to see old ruins, graveyards, ship wrecks, monuments etc, added to the scenery of the world as landmarks and to serve as haunted spots from where the undeads spring forth.