I think if I’m going to do something like this, I want to build on what already exists and alter as little as possible.
I agree with this general design principle, and apply it to all houserules I implement. What’s the smallest you can make your homebrew footprint while still achieving the house rule’s design goals. So, for me, I ask myself, “what do I want out of a system like Vitality and Wound Points?” For me, there are basically two things I want a system like this to do.
1. Create a clear distinction between abstract damage and meat damage.
2. Create a clear state of emergency players can respond to before their character is knocked unconscious or killed.
How can we achieve these goals while changing as little as possible? Well, we already have Hit Points that serve exactly the same function we want Vitality Points to serve, and we already have consequences for characters taking damage at 0 hit points. So to me, the natural thing to do is to make Death Saving Throw Failures be meat damage. Easy peasy, if you want critical hits or sneak attacks or whatever to bypass HP, have them cause Death Saving Throw Failures. If you want meat damage to have lasting consequences, add on the lingering injuries rules from the DMG, which wouldn’t you know, apply when a character gets two death save failures.
As for the second design goal, how can we make a state of emergency that players can respond to,!where they’re still conscious but they know the next hit is going to their meat points? Easy, just have getting knocked to 0 HP not automatically knock a character unconscious. Personally, the way I do it is with Concentration. When you’re at 0 hit points, you have to concentrate (as if on a spell) to remain conscious. That way its’s opt-in. If a player just wants to go down when they reach 0 and play out the death and dying rules exactly as written, they just voluntarily drop Concentration. But, if they want to go down like Boromir at the end of Fellowship, fighting with every last breath even as the orc captain fires arrow after arrow into their chest, they can make those Concentration saves to stay in the fight for as long as they still have death save failures to take. I also like how this makes it a bit of a risk-reward thing. If you choose to go down, you’re probably safer - you’re no longer an active target, so you’re less likely to get automatic death save fails from damage. But, you also can’t respond to the state of emergency, say by holding the orcs at bay while the hobbits escape, or by chugging a healing potion in hopes of buying yourself a few more rounds to turn the tide.
So that’s my house rule. When you would go unconscious due to damage, you can choose to stay up, but doing so requires concentration. (I should also mention, I give characters staying up this way disadvantage on attack rolls to encourage more defensive options during emergency situations). That’s it, cause I personally don’t like the whole crits and sneak attacks bypassing HP thing. But that would be a very easy, modular way to tweak my house rule to work a bit more like VP and WP. It’s simple, it’s entirely opt-in, and it does everything I want Vitality and Wound Points to do, and none of the things I don’t want it to do.
