I agree but...who said killing Sokolov is stupid or pointless? This is a man who's ideas ushered in an era of darkness for Dunwall's normal citizen. Why not give some players the ability to kill him and change the story with meaning and depth behind it? That will make it even better.
Keep in mind that I still agree with what you said but you are missing the bigger picture here. If we argue what the "perfect game" is, I would personally say that it should follow Dishonored's Chaos system both in gameplay and narrative that not only go well together but actually make each other better. Both sides have a point is all I am saying.
I see your point and do fully agree,
I was just taking his entire point up, the fact that you could do "anything", not just with the Sokolov Mission,
With that mission, I could somewhat see the story branch onward in a way, f.x let's say you currently have to kidnap Sokolov to find a cure to the plague,
or you need information or the liking. Let's say you kill him, then you don't have that info or the cure, which could change the ending of the game, or maybe the next mission as you have nearly no intel on what, where and when etc. BUT in general, I can't see it happening that you have total freedom, I mean even Skyrim has limits and boundaries, even Postal has it

You can't create a game that doesn't have a frame or doesn't have limits or rules at all

BUT in all fairness, the whole term of a "perfect game" or "freedom in games" is sort of a "in the eye of the beholder"-case in the end