[I don't see much market for a generalized non-fatal combat scheme.]
[color:"orange"]Good that it's notthing like what I'm suggesting then :P I'm just asking for the choice! The OPTION NOT TO KILL if I feel like I don't want to![/color]

Let me rephrase that. In the context of a group of evil wizards trying to bring a powerful demon overlord back into the world, both of whom are motivated by hatred and desiring only power and revenge, I can not see how you can *always* have the option for non-violent conflict resolution. Maybe you can banish zombies, mind control animals to send them far from settlements, etc, but the troll you sneak past today could be burning farmhouses tomorrow.

I also don't see where always having the option for non-violence conflict resolution would be a better marketing feature that having this option most (or even some) of the time. Sure, being able to talk your way out of a fight or sneak past enemies, etc is great for role playing, but I don't think there are very many people who would always want a non-violent solution (in a game) regardless of the situation or the type of opponent they faced. Some may choose that path if was possible, but few would lament it if it wasn't.

[color:"orange"]perhaps have a "pacifist" voluntary challenge[/color]

Given that there is a combat system in Larian's next game, I'm not sure how you could save the world as a pacifist. Maybe it could be designed in, but I'm not sure how it can done in a reasonable way.

[color:"orange"]Being in the middle of a war zone sounds more like a wargame, not an RPG[/color]

Most RPGs do involve an ongoing or imminent war, or invading demons, or some group trying to take over or destroy the world.

[color:"orange"]if the combat was fatal-only, no surrender, no quarter given, then it's harsher even than most war zones.[/color]

If surrendering was allowed in the game, you would have to be given an opportunity to escape fairly quickly, or it wouldn't be a terribly exciting game. If your opponents can surrender, and can not be trusted to keep a promise of future non-violence, are you to teleport them to some large jail that they can not escape from and that their friends are not going to try to break them out of?

There are many situations where not killing an opponent is just passing the conflict on to someone else, who (not being the main hero) would be much less likely to be able to handle it. Unless you invent some special places or talents reserved just for the good guys, anything banished can be summoned back, anything teleported away can be teleporter back, or your own allies teleported away. Any animals pacified can be angered and sent back to populated areas, etc.

From the background story for DD, written by one of the original evil mages, to the new generation;

In my heyday, we of the Damned lived and breathed with one purpose: to avenge the ancient wrongs done to our mighty Order.
You must all learn to direct your valuable destructive energies to a greater purpose!
It is your born duty to torture, butcher, enslave and degrade every last member of the Seven Races of Rivellon for what they have done to us! Think of them down there living contentedly in their productive lives when their true destiny is to be at our feet as groveling servants or chattel for our beloved demon allies!
I therefore command you with my dying breath to begin the quest for vengeance once again. Sow discord, spread misery and bring death to Rivellon. With the unity of the races truly sundered, there may be enough disorder in the realm to allow the return of our Lord Chaos.
Now go forth my children - undemine, spy, murder, rob and torture. Commit every evil act you can think of against our foes, retake the Sword of Lies and open the gates of Hell.
That way, I will be able to return to congratulate you properly - I, and all the dead Legion of the Damned.

Not much room for talking out your differences...