I’ve used Sanity in D&D before. I think these rules are OK, but there are three problems I have with them.
1. A minor gripe – the Mind stat being the “best of Wis/Int/Cha.” That’s a holdover from this being a conversion from a 4e article, you never do that “best of” stuff in 3.5. I always used Wisdom exclusively.
2. They try to hew just a little too close to the Call of Cthulhu Sanity rules. I like those rules, in fact when I do sanity I do it “largely” that way – 5xWIS. But then they carry over some things I feel like don’t make sense in the average D&D game. Penalizing starting WIS because of Knowledge skills is an example of “too much rules” and it’s even going overboard from Cthulhu- in CoC you only get this penalty for Mythos Knowledge, not just any occult knowledge.
3. And then they put a lot of SAN loss – too much – for only mildly horrific creatures. 1d8 for dragons, outsiders, and undead and 1d12 for aberrations… Even Mythos creatures generally did less. In CoC, undead are d4 to d8, byakees and Deep Ones are only d6… It’s the Old Ones etc. themselves that have big SAN losses. I think this approach makes it too much like “mental hit points” and doesn’t get the feel you get from CoC, where little stuff gets you a little, basically softening you up for the big horrid outer god. I know it’s hard to do in an article but they need to vary it more, a musteval guardinal is going to hit you for way less SAN than some gnarly daemon thing. The default SAN losses by creature type are way too high. Jesus, in d20 CoC the Dark Young of Shub-Niggurath are only d10, less than a carrion crawler apparently.
It’s not their fault, it’s just that the types are used too gratuitously in D&D. There’s these Medium lobster critters in Golarion called reefclaws. Dangerous, sure. But they are aberrations instead of being magical beasts or whatnot. Screws the rangers and now they are supposed to be super sanity blasting? Maybe if you don’t have any melted butter…
I do think the atrocity level of SAN loss is appropriate. I’d like to see the list expanded; in my experience this is the best place from a storytelling point of view to deal with Sanity. The list seems to “wuss out” and eliminate bad things characters can do. Witnessing a murder or being tortured gets a SAN loss, but what about murdering or torturing? One of the main points of using SAN is to show the consequences from being a big ass evil freak.