I affirm what others have suggested:
1. re-examine your inspiration for starting this thread. Are you irked at HP recovery mechanics
specifically, or at pacing
generally? Could your irritation be assuaged through other mechanical means than HP & HD?
2. talk with your players. As you know, it's all about the enjoyment of everyone at the table. They may be just as irritated, and may have suggestions.
My specific advice is based on what you wrote here:
Piratecat said:
The idea is that if you bed down when beaten up... drain your resources somewhat on the second adventuring day, emulating wear and tear on the characters as they stay out being big damn heroes.
I recommend, as others have, you take a good look at the Exhaustion rules in Appendix A. "beaten up", "drained resources", "wear and tear", "stay out" all sound exhausting.
Some mechanics:
1. take one level of exhaustion when crit.
2. take one level of exhaustion when dropped to 0 hp.
3. take one level of exhaustion when spend more than 1/2 HD at once.
4. take one level of exhaustion when spend more than 1/2 HD cumulatively in a day (stacks).
Using all four would be super punishing. But I think it'd be worthwhile to introduce one or two of the above, as a test. See if they provide the feel you're looking for, and deliver more fun for everyone. Maybe adjust by allowing con saves after a fight to mitigate combat-inflicted exhaustion, or some mechanism to spend HD to remove levels of exhaustion.
I know, as a player, I'd *like* a seasoning of non-HP debilitation. Makes combat a bit more scary, as even a kobold can crit. A dash of death spiral, and emulates the efficacy of pack attacks / death by a thousand cuts.