For full context, what I have in mind is another historical game (no magic or monsters), this time set in 17th century London. Think The Musketeers, crossed with The Scarlett Pimpernel, with shades of Marvel’s Daredevil and Arrow (the TV shows). The PCs are masked vigilantes, going out beating up criminals and making their ward a better place.
I want the PCs to generally default to not killing the people they fight, and have the mechanical underpinning to be able to do that.
Furthermore, a lot of the people they get into fights with won’t necessarily be trying to kill them either. Although there were a lot of young men wandering the streets at night, drunk and armed, in those days.
But unless someone pulls a sword, knife or pistol, the proceedings should be less dangerous to all concerned.
The existing rules go some of the way, and indeed EHamilton you make a good point about not separating them preserves certain useful nuances.
I should add, we decided not to use the Mortal Wounds table, except as a last resort when a PC has failed a check to die, after our first encounter with them. The results they produced were incongruous with the injury sustained in the first place, and it just didn’t fit.
I do use a house rule on hit point levels, adapted from D&D4e; at half your total you are Bloodied (-1 to hit, Proficiencies and saves, reduce move by 30’); at 0 to negative CON score, it’s -2, reduce move by 60’ and Fort (Poison and Death) roll every round to stay conscious. Fail or go into more than negative CON score and it’s unconsciousness, bleeding, possible Mortal Wounds.
I also use non-rolled hit points - max hp at 1st level, 1/2HD at every level thereafter up to 9th. So the variable comes from damage rolls.