Crimson Longinus
Legend
I think this favours casters a lot. The main resource a front line fighter is their HP, the main resource of a caster is their spells.In thinking more about this, I might just bring back AD&D's resting mechanics. All resources recharge with an 8-hour rest (RAW) except hit points (house rule). Those you regain at 1/day of rest out in the wilds or dungeons or 3/day of rest in civilization. It seems to hit all the right buttons. PCs can just keep pushing ahead if they want, but it costs them resources (potions, spells, etc) to heal to full (or near it). But it also causes the PCs to behave a bit more like real people in really dangerous situations instead of unkillable, infinitely regenerating superheroes.
This also reproduces the utterly bizarre AD&D effect, where the high level characters take way longer to naturally heal than the low level ones.