The question of world defaults is an interesting one. I think that can actually be taken up in a separate thread, otherwise future searchers of the forum might not notice it here. The link to that thread is here:
World Packages - ConceptAs for the interpretation of Hit Points, yes, there are a variety of ways I've seen Hit Points interpreted, that's true. In my case, for Elthos (ie - my world in in the Elthos system) I have it that Hits are the toughness of the Character. The difference between the 1st Level Peasant and the 4th Level Warrior, and the reason the latter has more Hits is because tough living and hard experiences have taught that character how to resist the Shock of combat. The 1st level guy can only take so much shock. Hit by a troll for 8 hits? He can not take the shock, his brain shuts down, nervous system goes into override, and his heart stops. He's dead, not from the wound necessarily but from the Shock of having been whacked off his feet by a troll with an ax. If that happened to either of us... well the results might be the same. However, the 4th Level warrior, having been hit by many weapons and endured many wounds and blows of combat (or the equivalent) has raw visceral Confidence. Remember that in my conception Confidence is what is actually being accumulated with Experience. And so our 4th Level Veteran gets hit by the same troll, with the same force, but instead of being killed from the Shock he is thrown off his feet, with the same gaping wound... yet he not only does not die from the shock, but has the grit, the nerves-of-steel, the courage and determination to get up and swing at the monster again. So the way I visualize it is that the Hit Points are related to a combination of physical toughness, combat-confidence, and mental fortitude. The dodging and parrying I have as separate things, where the blow missed, and no damage was done. I think that either interpretation could work, but in my case, I want to add Parry Dodge as a Skill because of this, and because they have internal limiters that I like. I think it will make, when we get to it, combat tactics a bit more interesting... especially when the combat maps are used, and the movement is taken account of in detail. We'll get to that again sometime, I'm sure.
As I see it, Elthos can get pretty GRUPSy, and my own goal with my world is to bring it to a low to mid level of GURPSishness, and not leave it in the default super-pasteurized state. Of course the beauty of the system is that after trial and error I can change my mind, and remove or modify the skills to what makes sense as we go along. And of course other GMs will do the same for their own worlds. To me, that's the beautiful thing about the ODS... it lets each GM decide for themselves what fits and works.