I'm sure this has been suggested, but the ability to make parties and send them out to different areas, perhaps even "dungeons" that are four person (or however many) that have their own item drops.
Anyone know the name of the song from the puzzles? The "desperate" sounding one that sounds like it has violins. I looked up the composer and he's solid as hell, but I can't seem to find that one.
 "Idle Raiders"){kind=icon}
 "no-one has to die."){kind=icon}
 "Days 2 Die - The Other Side"){kind=icon}