There's an important difference between offering options and telling the group "do whatever you want! have fun!" and leaving them stranded. 5E does the latter, actually designed games do the former.
As evidence by all the people playing it.
I'm not the one being asked, but I did play a game with both sanity and madness rules. And I agree that they're garbage.
There's a laundry list of issues I had with madness rules (sanity is serviceable, but far from being good):
- It's absolutely unclear what calls for, well, madness. Ok, aberrations with tentacles probably are madness-inducing, but what about other things? Is something like discovering that the town you've been living your whole life was an illusion all along mind-shattering, or is it's just "who the hell had enough time and 6th-level spell slots to do that?"? That's not exactly issue with madness rules themselves, but it's an issue within a context of D&D. When you have a dude who can hurl fireballs and build life-like major images, the line between "normal" magic and things that defy reality starts to get kinda blurry.
I feel each individual campaign should decide this for themselves either via GM fiat or group decision, but if you need the book to tell you here are the suggested causes...
Sanity Checks
-Deciphiring a piece of text written in a language so alien that it threatens to break a character's mind
-Overcoming the lingering effects of madness
-Comprehending a piece of alien magic foreign to all normal understanding of magic
Sanity Saving Throws
-Seeing a creature form the far realm or other alien realms for the first time
-Making direct contact with the mind of an alien creature
-Being subjected to spells that affect mental stability
-Passing through a demiplane built on alien physics
-Resisting an effect conferred by an attack or spell that deals psychic damage.
IMO this is more than enough of a framework of examples for me to extrapolate from for my own needs. I don't need the game to give me hard cases because my world isn't the same world as the designers.
- Short-term madness table often produces results that are just stupid and belong to slapstick comedy and not lovecraftian horror. A character that starts to eat naughty word because they've seen an alien visitor from the Great Beyond isn't something I'd expect from a cosmic horror story.
This isn't slapstick if it's not roleplayed for comedy... it's strange off putting and is similar to many portrayals of Reinfield in Dracula media when he eats bugs or other disgusting things.
- Long-term madness often table produces results that are either just debilitating (ah, yes, falling unconscious for 1d10x10 hours is so fun) or largely meaningless. And both categories are something that I'd expect to happen to a secondary or a tertiary character, not a protagonist.
So we want mechanical teeth... without teeth?? The unconscious for hours is a genre trope...are you serious??
- Indefinite madness table produces nothing but gimmicks, that are, again, much more suitable to NPCs, not the PCs.
Nope, it trusts the player to roleplay the actual flaw just like some of the other games presented here... and honestly for an indefinite madness I think it's the best approach since player buy in is crucial.
- And, most importantly, there's zero incentive to seek madness. The rules punish the player for doing things they're supposed to be doing -- y'know, meeting fish people, deciphering evil books, and looking beyond the illusory veil of comfortable "normality".
Huh?? You seek it because you need to... not because you want to.
Using madness rules not only ain't gonna turn 5E into a cosmic horror story generator, but place additional obstacles on the way.
I'm sorry you had such issues with it, but it did work and will be working for me when my campaign starts back up.