I actually think games are more interesting though where you can make it through the entire game without making a single kill. This is why I'm actually interested in laser stun-mode mods, tranq darts, and other ways to use fatigue instead of death to deal with people, and only killing when it's absolutely necessary, when there's no other choice. This is perhaps what I found most interesting about Deus Ex.
Myself, I'm in it for being a detective, an ambassador, a diplomat, and a scholar. Combat is always my last recourse. I have no objections with including lots of combat, but I wouldn't be the biggest fan of any mod that made heavy combat non-optional. That at least didn't give the player the chance to avoid it, no matter how crazy/bizarre that chance is. I'd still enjoy the mod, especially if I could do the combat without killing, but I find the most fun playthrough the one where I can say "Right, I got to the end killing, what... eight people? That's likely a hundred-thousand less than most people managed." >_>
My favorite part of a quest: The End.
I'm not much of a quester. Sorry. I just want to explore and kill.
See this is what will make it difficulty to do. Some of you love to wander around talking to people and learning stories, while others just love the combat and finding cool places. Though, with thorough enough scripting I could please everyone. Its possible to make a huge battle that you can avoid through persuasion and barter/speech/charisma whilst also having little areas of people to fight, where you could just knock them all out, take what you need, and leave before they recover.
I am almost smack dab in the middle here. Which I think will be a huge advantage for making this. I want a good story and some interested people/dialog to back up the quest. While I also really enjoy combat, and if I cannot convince the person through speech, I am more than happy to convince their separate body parts after the fight.
I like quests that involve a decision.
Kill the villain or let him escape and save the hostages?
Fight through the barracks or sneak through the irradiated tunnel?
Recover the technology to help people or destroy it so it can't be misused?
I love these kinds of decisions too and intend to put many of them in my mods. I love games like the earlier Splinter Cell's where if you had to get through a room, you could just go in and shoot/kill all the guards inside, or crawl through some vents over them and get past undetected.