Geromino: Thats not even how it works in reallife.
A medieval warrior would have worn a helmet, many of which have been insanely protective. Okay, many people would wear open face helmets because of the many advantages (breath, sight, hearing), but even so then you have to actually attack the opening for the face specifically.
And obviously warriors fled from battle all the time, so that doesnt make sense either. The muscles you need for running are different ones than the ones you use for fighting.
I'm complaining because I'm sure the people who designed this probably thought this would be "realistic".
Helmets do reduce the head hit damage, but as it's a guaranteed crit with a x5 extra damage multiplier on the damage it will usually be like 10 armor vs a 50 damage crit while your max HP is 60. So it will still do an insane amount of damage.
As far as realism goes, agreed, with the exception of blunt weapons. Helmet isn't going to do much against those. No need to penetrate the helmet when all you need to do is just cave it into the opponent's skull.
As for stamina, you can regenerate it in combat.... by standing absolutely still and doing nothing for a while. Stamina in this game is consumed by running and casting spells. Melee combat does not drain it, but it only regenerates if you stand still/enter passive stance. It could be possible that with focusing level ups on stamina, one might eventually start being able to outrun enemies. But to this point, every wild animal, goblin or orc was able to keep up whenever I did try running. Even big beasts like Trolls/Ogres. And given how drastically XP requirements for anything scale up in this game, dumping points into a stat that will only allow you to run away does not really seem feasible.