That's one of my main gripes with Skyrim, gameplay-wise. Fallout New Vegas, for all its faults, managed to not have a single essential NPC (save some securitrons and children, eh...). You could literally walk up to say, Caesar, and blow his brains out, if you didn't care for his particular questline. The rest continued just fine. Why, oh why, can I not do that to Maven Black-Briar? And essential COs are just ridiculous, what is even the point of that once the CW is over? Immersion breakage like woah.
I'm fine with essential npcs here and there but not too many like Skyrim.

