The eight hour healing thing.
Look, I know D&D has never been about realism. I've been playing in one form or another for over thirty years. I remember holing up in a dungeon room for days on end, healing a point a day.
I remember having at least one cleric in every party.
Which is the same thing, really.
But now, with 5E, you take seriously life threatening wounds, take a nice eight hour rest, and boom, you're back to full! And it's killing me!
Take an 8 hr nap and you'll be fine with it!
Don't get me wrong, I understand why they did it, and I love the fact that it keeps the game moving. There's a lot that's GOOD about the eight hour heal. The problem is, it is the one thing in the game that I just can't see happen without my eyes rolling back into my head. I can rationalize everything else in the game that defies logic and realism. I get that the PC's are Heroes. I get that hit points are not meant to represent just how much pure physical damage you can take.
You want to focus on that last bit, because that's where successful rationalizations for hps & healing can be found.
There's got to be a better way.
Hit points are one of the most abstract things in D&D, perhaps the major mechanic that most clearly illustrates that D&D is not and cannot be made into an actual simulation ('process sim' at the outside), and, yet, they're actually one of the most effective mechanics D&D has ever brought to the table. They model the 'plot armor' that keeps protagonists alive in fiction, without completely eliminating any sense of jeopardy or risk from play. As whacky as it seems when you try to force it into a realistic model of injury, it's a very good sub-system for what it does. The thing is, what hit points do - negate hits - isn't quite as clear from the label 'hit point' as it could be, and that the label 'healing' is entirely at odds with what merely restoring hps would represent in the fiction.
Before I get into my idea, I'd love if anyone else has had this issue and has resolved it, either through coming up with some kind of reasonable explanation, no matter how tenuous.
Hit points are mostly about the capacity to avoid injury, not endure it - a limited last-ditch capacity of luck/fatigue/whatever that gets used up quickly. Unless you're making deaths saves, you haven't taken a remotely serious injury. Once you're no longer making death saves, that serious injury that threatened your life is stabilized and no longer affecting your ability to fight/adventure/etc. You don't have to completely, literally, heal that injury before your capacity for avoiding injury is fully restored. That's all overnight healing represents, re-charging that capacity. Likewise, it's all most healing - Second Wind, Healing Word, etc - represents. 'Healing' is prettymuch a misnomer.
So, narrate appropriately, no serious wounds until 0, then one possibly-fatal wound, until you've made three death saves or been brought back up to 1 hps - at that point, you have a serious-but-stable wound. You can narrate that has taking weeks to fully heal and that it leaves a scar, if you like. Also, don't narrate healing, whether magical or non-magical, as making wounds simply disappear. Spending HD or resting 8 hours is just that, resting, you recover from fatigue, you recover your spirits, you're ready to face battle again. HP-restoring 'healing' spells, especially those like Healing Word should, likewise, be narrated as infusing you with positive energy/divine inspiration/etc, not making wounds vanish. More powerful effect, like Heal or whatever they're calling Regenerate these days, can actually be narrated to make wounds vanish.
So please understand that I'm not out to take away the eight hour heal. I love the fact that it keeps the game moving. What I need is a rational or a mechanic that makes it work. So of course I'm looking into something magical.
Considering that you played in parties back in the day that had no choice but to rest for days on end to recover hps, I think the problem with the magical solution should be obvious: not everyone wants to play a magic-wielding faith-healer.
If you want to 'keep the game moving' you'll still be forced to.
I'm also not looking to cut into those caster's slots, so I'm thinking it would be a cantrip.
Ritual would be the obvious way to go, there, that's exactly what rituals are for: spells that take a long while to cast out of combat and don't use up slots.