Just a funny little idea here.
Everything has 1hp. That guy? 1hp. That rock? 1hp. That eldritch horror from the 5th dimension? 1hp.
I was thinking about lethality. You can kill any individual with a rock. The hp abstractions is silly, although I recognize what it is useful for.
So the point is that each thing has its own “vulnerabilities”.
A rock is only vulnerable to a bigger rock. That guy is only vulnerable to what can get through his armour and his ability to dodge. That eldritch horror? Idk, 6th dimention stuff?
Anyways, just some silly thoughts.