Ok, so, sure, if you take unkillable NPCs out you can ruin the game and quest progressions, yaddayadda. You might tell me to go back and play Morrowind, but, listen, it would add to the realism if they brought back the ability to kill anyone. The solution for not accidentally screwing up something in the game by killing important and quest specific NPCs, is to have a symbol on them that marks them as important, so you'll know, but the option to kill them would still be there.

Say you wanted to kill one of the Jarl's in Skyrim and take over their throne. You can't. I just think the option to kill anyone SHOULD be there, just for role play purposes and to improve immersion or realism. Anyone agree? Like I said, the option to kill anyone would work out just fine if there was a way to distinguish between important NPCs.

Also, I'm perfectly aware that there are mods for this very thing and just about everything. So yeah.

It's not so much that though. Morrowind's NPCs were completely static, and dynamic events just didn't happen. In Skyrim, we have active AI schedules where NPCs can die, dynamic dragon attacks (and vampire attacks and such) and all manner of nasty things waiting to kill our lovely main quest essential NPCs.

Skyrim slowly moved away from Oblivion's "everyone's essential" attitude to making some NPCs "Protected", in that only the PC can kill them. Still, I agree that there are far too many essential NPCs still.

SomeWelshGuy is exactly right. People like to frame this as a "player-killing-NPCs" issue, but it is not. That is not why we have essential NPCs. Oblivion introduced essential NPCs to prevent the game itself from killing NPCs.

And Skyrim has taken many steps forward from Oblivion in this regard. First, there are fewer esential NPCs. Second, Skyrim introduced a new mechanic called Protected NPCs, which Oblivion did not have. Protected NPCs can be killed by the player but not by the game.