Having someone controlling the decisions can create a forced, but still natural story change or at least a change in tone or emotion. An example is that in Left 4 Dead, they use the AI Director. The purpose of the AID is to have multiple runs of identical levels feel different by having an entity gauge what you as a player/party can or can’t take right now, and how it can push you to your limits. Aspects such as these could even be used in future to naturally change the entire storyline of the game without relying on preprogrammed branching paths, shifting the game’s level of intensity/urgency and giving the game replayability.
One way to naturally reach this goal is by making this entity player-controlled. I was recently involved in a project where a sole dev was trying to build a DND-esque world that one player controlled live as the ‘game master’ and the others played as a regular RPG. Unfortunately I had to resign from the project due to personal issues, but it’s great that there are some people trying to push for game mechanics that should be obvious but are only getting considered 30 years into the piece.
An easy example (but rarely seen) is corruption or destruction of the game world in mid/end game, and the player needs to combat it (This was a technique used in UFO Aftermath that increased the replayability and the player’s level of urgency about 20 hours into the game. Look up “UFO Biomass”). Of course, for a game to be the most replayable and impactful each time, you’d have a few of these events that the game picks from to unleash on its player when they’re just getting the upper hand.
haha