Creative directors and other Artists in video games (my experience) tend to like to 'stamp' the visuals of a game with a certain aesthetic, from their own inspiration. Generating 3D models (offline, not in game) would be a great start, but in the end it's only a 'rough' draft and will likely go through the same amount of work to get to a final 'approved' visual state.

Unlikely in the near future, highly probable in the longer term. Imagine writing a script (movie) and having the AI generate the characters ... storytelling to a new level.