Celebrim
Legend
And a likely reason for that is the time and effort it takes to assemble content. Even with the best tools, it won't be fast enough for the players ability to zoom around the map looking and touching everything. Just like they do in Skyrim, and unlike that they do at the table when then walk into that imaginary pub.
A computer with this sophistication of Watson could achieve at some levels the same understanding of, "You see a pub.", as a player. Such a computer could respond to, "You see a pub.", by bringing up an example pub for you, and indeed could learn from trial and error what you most likely had in mind when you particular said "a pub". You could also correct it, "No, a pub in a rural village.", and have it return an example.
Eventually, a helper like that could learn to share the creative space with you, not merely retrieving images, but modifying them, so that if you said something like, "Ok, like that, but more ivy on the walls.", it could search for an image with ivy on the walls and extrapolate where ivy might be on this image. Or you could say, "Ok, add a second story", or "Put a sign with a green dragon hanging above the door." A really 'smart' such program could respond to things like, "Extrapolate a floor plan."