What the OP is proposing - at the level of content complexity of, say, Skyrim - would be
obscenely difficult to do. That is, if you want the game world to actually function and generate even halfway-interesting plots and quests for you without immediately breaking them. It's orders of magnitude more difficult than what BGS has done with previous games. Of course, nothing is impossible, but it would be so ridiculously hard to make it work that it would be budgetary suicide to even attempt it with current software technologies. If it served some purpose outside of entertainment I could maybe see it happening, but since it doesn't there's just no way anyone in their right mind would put those types of resources into such a project.
I mean, it's not a new idea. It's the sandbox game model taken to its logical conclusion. We're just not anywhere near there yet. When we can write software that can answer the question, "ok, but is it fun?" we might be approaching something like this. Until then, don't hold your breath.
