JP: I still have the same issues: Creating a roster of characters is like creating a roster of paints. The thing creating the constraints is not actually the generative force behind the art.
We don't deny authors the title of artists simply because they work within defined rules of grammar and vocabulary, nor do we argue against western musicians being artists simply because they work in a scale with 12 semitones.
In terms of pen and paper RP, no, I think the player should be the player, but if you think the Dungeon Master is the only one telling the story there I'd have to bitterly disagree.
As far as the artistic experience goes, I think that you extrapolate too far in saying that because it can be boring, it must be boring. Stacking blocks is boring. Tetris is not boring. Running a farm isn't always fun, but Harvest Moon is fun. Getting shot at I'd imagine is generally a bummer (though arguably more exciting than the other two) but Call of Duty is fun. Games are about taking experiences that aren't necessarily always engaging in real life and distilling the amazing bits.
TG: I also want to say that I do think that players are part in creating a story. So I agree there, but I disagree that the process is just like an artistic storyteller. I argue instead that it is quite unlike that and more like the activity of experiencing other media, just that it is much more powerful, because of interactivity.
And regarding Tetris & farm analogies: Yeah, you are correct, Tetris is not at all like stacking boxes. And the reason for this is that it does not strive to be like a box-stacking experience. Same with farming. You do not create a videogame about farming with the goal of making it as much as real farming as possible. And in the same way, you do not make the player emulate the work of a "normal" storyteller, but you strive for other goals instead.
However, I think the analogy is flawed. Because creating a game about a story is not the same as creating a game about a storyteller. If you were to create a game where the player had the role of, say screenwriter, then I have to agree that you can view the player as a kind of artist, and try to distill that experience.
However, that is not what most videogames try to do. The goal is to put the player in a virtual world and make them have the most immersive and powerful experience in that world based on certain characteristics setup by the designer(s). I do not think it is helpful to think of the player as a storyteller in this kind of situation. Instead the player is very much an audience and given input from player, the videogame's job is to create the most compelling narrative possible, within the preset framework of the intended experience. Sure, the player decides a lot of things during the journey through the game, but he does so given his/her role inside the virtual world, not in the role of a co-storyteller.