I like the game. I would like this sequel. Either a new story and new investigator. Or if you're daring the same investigator.
Get through one module and your character transfers to the next with your skills. Just add more skills, more difficult checks. Didn't play first module or didn't get through sane enough. Replay Pierce in new module to build up from his base skill levels. Simple really.
An ongoing Cthulhu campaign, at least a continuing series of one-shot investigations. Plus did you see how many skills there are in the tabletop rpg?