What about using the Burning Wheel system, or more accurate, a watered down Burning Wheel system (much like how MouseGuard plays)?
It is a simple system that relies heavily on storytelling which might benefit this type of game.
I am really interested in this, and would love to see more of it, sadly because I am a rather new played in any RPG, I am still a learner and don't have much knowledge to provide.
On the subject of an Illithid ressurecting a fallen party member-
"...because every one knows that Illithid are notorius for being Clerics."
'The Wings of Death beat overhead,
Here to collect victims of The Red'