I am a huge fan of sneaking and sniping, but It's getting too easy! What if we had snakes in tall grassy areas and wilderness that if bitten have the same effect as getting to cold. You could also make an anti venom item that's just as rare. I think adding this element will make one a little more weary about crawling around. Another idea I had was 1 random spawning bigfoot for every server, who was fairly powerful requiring 2 or more players to take down easily. It would be fun to go on bigfoot hunts, and obtain an item for proof of your kill along with plenty of food. Last but not least, what about being infected by zombies after death your body turns into npc zombie with your gear. Even only a few items would be neat, and make a unique experience recovering your gear.