Maxperson
Morkus from Orkus
What the DM feels is impartial can in fact be impartial. Knowing whether he is or is not being impartial doesn't change the level of impartiality that the DM is giving.But all of those responses are 100% sourced from the DM. There is no impartiality, other than whatever the DM considers to be impartial. Those "naturally emerging outcomes" are completely coming from the DM. They aren't natural at all. They are 100% dependent on the DM to create them. That's neither natural nor impartial.
True, the DM can strive to be impartial. Absolutely. But, there's no check on that. There's no way to know that the DM is being impartial or not. We can hope that the DM is being impartial. And, I suppose, so long as the players are happy, questions of impartiality are largely moot. But, at no point is this process impartial or natural.
When I run NPCs, I know the personalities that the important NPCs have, as well as their motives and desires. I will roleplay interactions with the PCs as someone with those traits would react. Personally, though, I have no desires for how the outcome will be.
If the party goes to the local lord to persuade him to do something, I don't desire them to succeed. I don't desire them to fail. I don't desire them to partially succeed. I don't desire a fight. I don't desire a fight not to happen. What happens, happens based on what the PCs say and do, as well as what the NPCs goals, desires and personality are. It's fun to see what develops.