Logical conversation trees driving the LLM context seem way more reasonable to me than the other way around. But then you are adding a component of "how can I

Logical conversation trees driving the LLM context seem way more reasonable to me than the other way around. But then you are adding a component of "how can I interrogate the NPC?" to the game. Anything you add to a game makes it a different game, and not necessarily a better one.