what is the objective measure of pushing a story forward in an enjoyable way?
Pulling back the veil I realize in storytelling I realize the traditional scene is the GM set up and the Players decision. The scene stalls when the players decide on a path that leads to no escalation, the story or plot doesnt move, or when the whole scene is scrapped.
Mechanics like in 2D20, Fate, and other Storytelling mediums Push the scene to the Players and the GM becomes an editor - correcting the scene if it lacks Risks/Threats, Tension, Stakes, Clear Conflict, Engagement for the other Players etc...
GM "Yeah ok, so your going to go to the Kings Court/ Dragon/ High Priest with this? Ok what are the stakes and risk?"
Ideally the players DONT WANT the rewards handed to them. That there is a cost to what their PCs want and its in this Trade Off where character development happens.
One of the weird things where the people who Play TRPGs need to align are "Your PCs motives are that they want X - but they have other Conflicting fellow PCs and they cant just get what they want for nothing right? What development and trial will the PC's go through? What will make the Player want to experience some set backs for catharsis?
The Dice is to determine if Unlikely or Likely events happen. That what would be unusual or usual happen to the character. It is to organically create the setbacks that build up the story.
In fact if the challenge is very overpowered to the PCs, we wont beleive the PCs are over their head unless the dice statistics show that and their strategy show that. That our own ability to judge the story for engaging is being able to accept the likeliness of the events.
What objectively moves the story forward - is the mutual agreement of the Parties invovled that there was Tension and Catharsis. That we have Tools in the game system that allows us to take on my Tension (Risk and Obstacles) for Catharsis.
In storytelling - Failures are the backdrop of what would be a High Stakes scene!
That the Players agree in a criteria where they will have something to modify the Odds as they take on setbacks. So that the setbacks are not indefinite.