Hit Points as Regenerating Armour did not work well enough to merit its inclusion as an Optional Rule because it required more recordkeeping than it was worth. When used with
Hit Location Body Points, it performed the same function as normal Hit points: to ablate with incoming damage, preventing bodily harm (or structural damage). Projecting its effects, HPaRA would have made the optional
Condition-Levels method of tracking Body Points in a slow 'death-spiral' a much longer, drawn-out affair which also would not have provided enough good with the bad of additional recordkeeping.
As it stands, Playgroups which prefer a kinder, more cinematic accumulation of wounds should choose the Condition-Levels method, while goreghouls should chose the Hit Location Body Points method; the OSR will simply use Hit Points and
Shields Will Be Sundered anyway, so that resolves itself.
Being a goreghoul, nitpicker, bean-counter, I feel as though that portion of the entire expanded Combat section has worked so well at its design purpose: to model non-cinematic, mundane body trauma in a quick fashion while still incorporating Hit Points' intended function (essentially 'extra lives'), and Encounter Critical's
Armour
Saving
Throw system (Save for Half/Save for None). My addition of 1/10th AST as Damage Reduction makes wearing any applicable Safeguard (Armour, Screen, Shield, etc.) useful even without a successful save.
The Survival Roll at 0 HP now applies to 0 Body Points, or other, catastrophic injury (terminal Head or Heart shot, etc.), and, as written in EC, reduces the PC's future good luck across the board.
After years of running Saving Throw as after AST, I have begun to run it first, which makes the Mass Combat section easier by simply stating that only Hero, or exceptional figures receive the personal Saving Throw (PST). Now, so-called Skirmish, and Mass Combat can be treated with the more Armour Class-like roll by the Attacker rather than the owning player's AST.
Action Points have changed EC's: Move, Melee, Missile routine to a Player determined sequence, but coupled with the Initiative Advantage mechanism makes this a dynamic sequence where going first doesn't mean that combats become one-sided affairs. You'l have to see how this works in your games, but I think it will be remembered as an innovation.
Meat Healing and Stun Recovery and Fatigue and all of that is another topic.
Later,