I think there is an interesting possibility with Perma-death for Npc crew members. It would take tweaking the a.i. a bit but I think if you were to exclude crew member npcs from things like lava damage then it would just be balancing enemy and monster interactions to make it feel fair. the benefits of adding a something like this is that it would really synergize well with the crew member mechanic significantly improving peoples' immersion and emotional investment in the characters making them less annoying and more endearing, think of x-com as an example. you're given only a bare minimum of info about your recruits, but their mortality adds so much more to your investment into them and the game as a whole, I still remember when my sniper "Big Mamma" died, she'd been there since the beginning and when she was taken down it was impactful.
