Based in the Wiki, the hitbox discussion doesn't seem finalized yet, so I thought about how one would maybe try and balance different sized characters with different sized hitboxes as a test towards how damage is calculated for projectile type skills and abilities.
https://ibb.co/xYHTF30
I made a example scene with two different sized rigs to illustrate - imagine the one to the left is an ORC model, and the one to the right is a smaller Dwarf model. If the hitboxes were this size, it would obviously be an advantage for the Dwarf, as its way easier to hit the Orc overal with for example an arrow.
So my suggestion for the devs is to test out a duplicate hit-detection system for the rigs.
Kinda like this:
https://ibb.co/q12wn3d
Here we see two bone systems (used as hit-detection) within the bigger Orc model, and to balance out the difference of the two characters, the outer layer of "hitboxes" in the bigger model takes less damage than the smaller ones behind it. The smaller bones are calculated to be as big in volume as the smallest character.
If an arrow hits the legs of the Dwarf model, it for example does 50 damage.
If an arrow hits the outer edges of the same leg for the Orc, it does 10 damage. Only if both hit-boxes are hit, it does the total 50 damage 10dmg for outer hitboxes and 40dmg for inner hotboxes, so to do max damage on the Orc model, you have more or less the same "volume" of area as the Dwarf model.
An alternative to this, while still trying out double-sets of hitboxes would be to try and figure out where "critical parts" of the body was. This way we can remove some of the hitboxes and only place them logically in the rig where "big" damage makes sense. Heart, lungs, liver etc. But the main point is to calculate the overall volume total that is used in the smallest Playable rig and its hitbox, to simulate the same volume within the bigger models and their hitboxes.