Ovinomancer
No flips for you!
I think, again, that the difference here is authorities -- yes, your players change things, but only can do so with your approval. This isn't a dig, it's a very important distinction and allows for types of play that use this tool to maintain coherency in themes and vision and events. It's exactly how I wield my authority when running games that have the GM role set up with this authority. This is contrasted by games where the GM does not get approval authority -- players can introduce things that the GM can, at best, challenge through the mechanics and, if the player succeeds, the player can assert this over the GM's desires. Of course, if running this kind of game, the GM should be leaving those desires at the door so this isn't a problem.Not merely bodily movements, no. The PCs killed Turnik Steeltear, ending his (and the Masked Ones') reign of terror over the village of Callallah. Mo talked the city council of Pelsoreen into altering the city's laws on debt-slavery more than they'd originally intended to. There will be no more Masked Ones created; there are explicitly a few squads of them out in the world, but they're limited in number and lifespan. I will (though I haven't yet) re-write the player-facing document for Pelsoreen to reflect the change in debt-slavery.
My dislike of AP-style play is, I think, well-documented by this point.
I don't fridge characters (or other important things) the players create in their backstories (see below) without talking to the players, first. There's been a discussion of whether killing the PC's brother (in your example) is an uncool move by the GM; I'm not a big fan, but I think established expectations at the table matter the most for determining cool/uncool, here.
So, in the examples I gave above, the PC/s pretty much decided what they wanted to happen, and made it happen. Turnik Steeltear and the Masked Ones were connected to a character's backstory; Mo decided the changes the Pelsoreen City Council were implementing weren't enough, and made a concerted effort to end the city's practice of debt-slavery by force of persuasion.
In the other campaign I'm running, a player established that there was a monastery/dojo in New Arvai called the Chiaroscuro Temple (I helped some with the name and the concept, as part of negotiating it into the world I'm running) as part of her backstory, and established that there had been an incursion from the Hells there. The history of the Temple goes way back, and the Hellish incursion plays well with the basic character of New Arvai. Another player, in his character's backstory, established a small town in a mountain pass. That town has been there for centuries.
So: In play, the players in my campaigns can change the future of the world but probably not the past; in chargen, the players can change the past of the world, but probably not directly the future.
As much as you allow and even encourage the players to have input into your games (and I'm the same way), it's more of a benevolent dictator situations -- you can always say no and that's within the structure of the game and the social contract.
I think, fundamentally, this is the difference -- can the GM say 'no', where can they say 'no', and for what reasons can they say 'no.'