Snipped from a post I made earlier today. Most that responded recommended that this end up in Suggestions, so here it is! All feedback, including ideas on where this could be applied, are welcome. Fingers crossed that this was already thought of!
Thanks for submitting a new suggestion! Please remember to give your opinion on this suggestion by voting on our suggestions page.
I don't know what would be more tense: hearing the sounds of cracking wood while camping at night, totally exposed to the elements, or the sounds of falling or shifting rock while spelunking. Of course, then there's the possibility of audible sensor alarms going off near your base, alerting you to some monstrous presence coming in (how loud or soft the sound is would depend on how far away the sensor was placed), but far enough so you can prepare defenses. That would still be pretty terrible if you were on a world enshrouded by a fog for most of the day. Many possibilities!
This is a wonderful idea and I support it fully. It'd make the game just that more real when you throw a rock in a cave, and here it's echo as it crashes about.