Thought about this some more and I have an idea. Maybe the temp drop can be tweaked to be a little less harsh (spending 10 to 20 mins outside and nearly freezing to death is pretty silly unless you are on the tundra or something). In addition to that how about if warming yourself by the fire has the after effect of making you immune to temperature drops for around 30 mins or so. This would have the effect of making people get a fire going every hour of game time and still have plenty of time to go raiding, gather more wood, matches, etc. It probably would encourage more teamwork as well several people could focus on gathering loot/raiding while others would focus on keeping the base camp supplied with wood. I like the idea of the temperature system but it should be something players have to keep in mind (like food/water) rather than something players have to focus ALL of their energy on.