I don't think an AI freely writing lines within the game is a good idea if the developers want to be certain that it won't ever produce questionable text. But it might be useful to produce much larger quantities of fixed texts beforehand using an AI and maybe let the AI change the wording of the text in real time based on context.

> I even think players will be able to interact with NPCs via voice (so no more “press square to Dismiss, triangle to Antagonize”).

A button press will always be faster and more reliable. It's clear that outside of VR experiments with control schemes are not very popular (remember Kinect?). It would be a nice optional feature for accessibility, but if it's non-optional I'm not playing that game.