The problem of low hit points on humans

[Taqwus]

...in particular, it gives a way of distinguishing those that between veteran heroes who are unusually good mostly because of their experience (and thus who may not have that much room to improve, instead of getting 5 stars worth of additional experience and bonuses) versus those who have more innate potential (ex. the extremely lucky, the assorted spawn of philandering deities, et al).

But ordinary humans... are humans. Doesn't really matter how hardy they are when they've just been disemboweled with a trident or bitten in two by a dragon. High Defense, maybe even innate Air Shield (extreme skill at missile dodging) or if Luck were more granular rather than 50-50 always, perhaps lower encumberance reflecting staying power... most aren't walking around after being almost entirely dipped in the Styx, or bearing arms from the forges of Hephaestos, or walking around with god's blood.