... conversation parsing; creating dialog content; making the input manageable.
... modelling a human being; motivation, personality and emotions.
... dynamic story generation; plot building blocks; player freedom.
... extending the parser; how much to simulate; emergence and unexpected solutions.
... knowledge representation; AI techniques for IF.
It would take a thesis (or more) to do justice to each of these topics, and I’m no expert on any of them, so I hope to learn a lot on the way.
There is nothing particularly wrong with the current state of IF, but it’s fun to explore what might be possible in the future and what it would take to get there.