The D&D system of "fine at 1hp, dead at 0" is - despite the oddness of the stark binary contrast - a useful game mechanic. It's nice and simple, and keeps argument to a minimum. Despite that I still think it could do with a little tinkering.
The simple fact is that a lot of casualties in any fight aren't actually dead dead, they're just incapable of fighting on due to shock and/or injury. Given that soldiers (for which read adventurers) are generally fit and healthy people, most of them - exceptional circumstances or butchering of the wounded aside - recover from life-threatening injuries if M*A*S*H gets to them quickly enough. I don't think it would harm the game to represent this in play.
In support of this I'll be stealing an idea from GW's Skirmish series of games (Necromunda, Mordheim). When an character you care about in any meaningful way - PC, Henchman, etc. - is reduced to 0 hp instead of just having them keel over roll d6 on the Hawkeye Pearce Memorial Triage Table below:
1-2: *blargh* I'm ded!
Unless you're using Fate points, or something like SuperNecro's heroic escape mechanic, the character is dead, dead, dead. Drape a cloth over them. Play The Last Post. Fight over their stuff. Roll up a new guy.
3-4: It's just a flesh wound! Oh...
Character is bleeding out and will die unless treated immediately after combat. If the character survives they have a huge f-off scar and a 50% chance of some kind of permanent injury as a momento of their barely cancelled appointment with the Reaper.
5-6: You dive like Italian footballer!
The puny weaky soft girlyman has been thoroughly knocked about, but is among the walking wounded. Give them some band aids and aspirin, and tell them to stop malingering. 0hp? Pah! There are people worse off than you sonny.
Sure, you can always roll on Critical Hits tables of positively Rolemasterine complexity if that's what floats your coracle, but I like to keep it simple. Roll d6, take yer lumps, move on with the game.