It is challenging to make praise worthy mechanics in games based off on the lore. I'm a fan of the mythos but the nature of games already spells adaptation limits to what the lore really is.
Games offer the players some sense of control but in the mythos, there is no control or control is an illusion. A game that really makes a player feel like the protagonist in the mythos would be something like, understanding nothing matters in whatever they do in the game, the game barely notices the player and if they do, nothing will protect them from the cosmic horror.
Because the mythos derives its power as far as human imagination can go, putting that imagination in concrete gameplay is already a huge limiting factor where the player's decision affects the outcome (not seen in the mythos).
Yeah, I certainly feel the limits in the Call of Cthulhu game's adaptation of the material. Chaosium's tabletop game is a better starting point than strictly sticking to Lovecraft's works, but that was one of the things that sort of rubbed me wrong with the game's ending. I almost would rather have a ending with no player choice than the way it was handled. The game did a rather decent job with building up to the ending, especially with some of the more powerful experiences, but it just seems to sort of forget that build up as you reach the very end of the game, which is a bit jarring.
The thing about trying to translate the lore into the gaming realm is that you lose a lot of the elements present in the lore. It won't be a game anymore without the illusion of choice and it certainly won't be fun for mass adoption when the things you do in the game never mattered. I don't think players that play games related to the mythos are geeky enough to understand the complexity of the lore itself.
As long as devs can commercialize something with the use of the mythos for marketing, there's not much we can do about that.
Never doubt the geekiness of someone else. That's not fair. :)