Hahaha
the more we talk the more it seems HP is just an overall problematic system in its presentation. A lot of its sounds like HP=meat, but HP=meat doesn't work with current HP recovery system... And even if you go back to old school '1 HP recovered per day' (which, strangely, makes recovery of stronger characters take longer than on weaker ones?!) instead and were to cut most healing magic and items, you would still run into the issue of damage not having an impact until 0 HP...
But if you try to be too simulationist you end up with one random roll disabling your character for months of in-game time, and even just a penalty from damage can lead to a death spiral where you just get easier and easier to hit the more you get hurt...
But since I'm more of a gamist I don't really mind that much, as long as it's INTERESTING.
Yeah, that is why, even though it is just a slight difference in mechanics and name, I love the SW d20 Vitality and Wounds. Vitality (HP) is your energy level, luck, skill, etc. which wears away from attacks and Wounds = meat (more or less). But, even then, you getting into the idea of "hitting and doing damage" without even necessarily "hitting."
Myself and our other DM often narrate hits as real efforts by the PCs to actually avoid being hit, the amount of "damage" representing the amount of "energy, luck, skill, etc." needed to avoid the hit (or lessen it to being "ineffective").
In a similar light, sometimes I narrate misses as actual "hits" but they are completely ineffective. The idea being, "Sure, you
hit him as in your punch made contact with his body, but he shrugged it off" (i.e. you actually missed, so deal no damage).
I would prefer system where a "hit" is a hit and "damage" is damage, but D&D and HP will never get there.
In that manner, the idea in the OP about starting encounters at full HP is basically like, "Ok, fellas, back into the fray!" and you charge into the next battle, feeling good and energetic and ready to fight.
With all the difference mechanics available, HP, CON, critical hits, exhaustion, conditions, etc. it seems like D&D could come up with a system that allows incredible 1500-foot falls and critical bites by dragons a
chance of killing even the mightiest of D&D heroes (I don't care of the odds are 1 in a million, the point is they would be
there!). The opposite side of the coin, is a system that can accomplish that, but isn't bogged down by making a dozen checks and such or tracking half-a-dozen numbers for its mechanics.