I can't see how, not unless it is a 'AAA' always online game or if the quests are cached.

I think the most amazing use of AI in games (specifically RPGs) will be with statistical models to crunch "planning" and "cause and effect" to draw players into plots, schemes and storylines and then to demonstrate the impacts of success or failure of the player's quest. Think economic simulations of a city due to the player's actions or sabotage where the player has crippled a port leading to the NPCs barking about hunger, prices and disease.