I'm a big fan of progressive health systems like Shadowrun or Mutants & Masterminds. My idea is to completely remove the wound threshold; instead, any wounds that exceed soak are taken as strain damage. The player then gains a critical injury with a roll value equal to the damage after soak, applying modifiers as normal. (activating a critical does not apply an extra injury)
Healing wounds applies to the strain threshold with the benefit of healing above their strain threshold. Excess strain is removed at the end of the encounter.
This seems like an small tweak that will allow for grittier combat in settings that need to be more lethal. I'm really interested in any recommendations the community has.