Thinking more along the lines of stakes, same as in social combat. What if the default for (heroic) physical combat is maiming instead of killing(or that killing takes some time after maiming, requiring failed death saves etc)?
So for example.
50% health is a flesh wound, with attendant status effect. Healing removes that. Also the same point that anyone not fighting for keeps to retreat.
0 health is a choice, fight on, or knockout. Choosing to fight on means you receive a mid-term(days) disability, and stay moving. Or you can be taken out, for a second flesh wound. Only major healing would fix the disability, hit point recovery alone won't do it
Dealing enough damage to bring the target to -10(or possibly a different death threshold, -10 doesn't scale well after all), the target takes a permanent major injury, and becomes unable to take standard actions. They can attempt to flee(and very well might if theres other allies on the field), but cannot contribute to the aggressive actions any further. At this point, also, unless healed, they will be making fort saves vs death. The saves get harder as you pick up additional major injuries.
Death occurs when you fail a death save.
Socially:
Minor - Getting the target to do something that doesn't go against his convictions. This probably equates to 4E's Bloodied, something that takes some effort to do, but you can feasibly accomplish in an exchange or two.
Moderate - Temporarily overriding one of the target's convictions or temporarily creating one. Might take a day or two to shake it off without followup. Equivalent to dropping a target to 0.
Major - Permanently breaking or forming a new conviction(e.g. converting to a new faith, changing a code of conduct). Equivalent to losing a limb(eye, horrible scar, whatever), though probably should be somewhat time consuming(and they'd probably disengage before this point).
Fatal - Personality rewrite, involving the majority of the target's convictions. Death equivalent, highly time consuming.
One question that comes up is how do you track social health. Are you wearing the target's willpower down to the point where they would accept various effects? Or is the focus of the conversation the health bar, so you cannot for example, wear someone down with arguments about Justin Bieber and then switch tack when they're low on willpower to convert them to Scientology.
Social defenses is another, base it off Will saves as a measure of stubborness? Or some other social AC? Add your offensive social skill to it?
Another thought is timespans. Social conflict can happen in a number of ways:
Conversational talk - Spans in minutes, generally low intensity, and often one-way.
Fast talk - Spans in combat time, high intensity, and aimed at prematurely ending conflicts. This mode probably needs to tie into physical combat mechanics somehow, or at least, having one side affect the other.
Written appeal - One party is only remotely present, using say...a strongly worded letter or a mindcrushing rune. Timespans are long there.