That's a very insightful take. I think an LLM would have some role in a good text adventure game, in terms of being able to understand any natural language input and respond intelligently. But as you point out, it would need to do so within strict constraints set by the game designer.

I haven't played with the most state of the art parsers that are available right now, so I wonder how large the gap is between a great parser and using an LLM to process user input.