Warbringer
Explorer
I think it would work very well for the setting, but would produce a much different style of play. I suppose with d20 cthulu you could do something closer to d&d ravenloft, because that still has levels. But chaosium cthulu would run very different. It actually might play a bit like hammer films, which would work because ravenloft drew a lot from that. The characters would basically be normal folk.
NPC only classes, E6 style ....
Initiative .. You win, you run; you lose, you die ....