Recently, there's a big trend in RPGs, especially the old school "clone" games, to insert massive amounts of Cthulhu-style themes and monsters into otherwise standard swords & sorcery fantasy. While games like Call of Cthulhu, which is true to the era, style and stories of HP Lovecraft and other mythos authors have done quite well, and stand alone optional sourcebooks, such as Realms of Crawling Chaos for the Labyrinth Lord system as fine, I've been wondering if there is a point where too much of this material harms not only the campaign it's injected into, but the material itself.
Two main points here:
First off, the "monsters" and great old ones themselves are supposed to be rare. Shocking and horrifying because they are not things one encounters on a regular basis. By featuring these monsters, curses and the related madness they cause at every turn, I feel a campaign does a grave disservice to them. They become mundane, just another critter to bash, loot and collect xp from. The mystery and horror is utterly lost.
Second, and more specific to a "normal" fantasy world like Mystara (or the Forgotten Realms, Greyhawk, Golarion, or whatever your preferred flavor is), the whole role of the Great Old Ones and their related beings is kind of moot. In the Lovecraftian mythos, the main reason these dudes pop up is because curious and foolish mortal men long for forbidden knowledge and power and conjuring up the unknown powers of ages long past is the only way to achieve their goals.
In a standard fantasy milieu; arcane magic, the binding of magical creatures, pacts with demons and devils, and faithful service to "real" gods and immortal beings who can grant wondrous powers in return all serve as paths to the learning and might the foolhardy summoners of Cthulhu's mad servants seek. So why bother venturing into a no-win situation that holds only eventual madness and destruction when there are actual easier and less risky ways to do it?
I have no issue with throwing in a bit of Cthulhu inspired weirdness now and then, but it should remain properly weird, horrifying and insanity inducing, and it should be thoughtfully introduced into the campaign to ensure you are not only preserving the integrity of the material, but actually furthering the development of your campaign.
Any thoughts? Any experience using the new breed of mythos-heavy material, such as the DCC RPG, which is "chock full 'o Lovecraft-style goodness", as they say?