System 1 has a highly narrativist focus, where each participant gets an equal share in telling the story. The players are allowed to declare certain things about the world to be true, including things that extend far beyond their characters’ immediate interests. The world exists as a backdrop for the story and bends and molds around the characters. What exists tomorrow, or beyond those mountains, is totally based on the immediate needs of the story, and left blank until filled in by someone during play. Beyond the world, the mechanics are also designed to support plot. The rule of cool is the norm, and the heroes can’t fail unless that’s how they decide they want the story to end.
System 2 has a more simulationist focus, where the emphasis is on world exploration, with the world being treated as its own entity with “solidity” and not subject to play-time adjustment. The duke’s secret invasion fleet is going to make it to the planet tomorrow, regardless of the fact that no one but the GM knows that, and that date isn’t going to change to accommodate what could be seen as a better story. The things beyond those mountains are either already drawn on a map, or they randomly determined based on geological and geographical probabilities. There is not a swamp there because that would make the best story or be convenient. There is or is not a swamp there based on how the world was pre-designed. The mechanics provide a consistent framework where results follow actions based on whatever passes for physics in that world, and neither players nor GM can alter the causally-determined results of actions.
Both of these could be considered high player agency systems. In the first the players have a high degree of influence over the course of a created story, the development of a world, and the outcomes of particular tasks. In the second the world and mechanics allow the players to truly explore a world, choose actions that have fairly predictable results based on known (to character as well as players) in-world physics, and experience accomplishments based on skill and luck, similar to real life.
Both of these could also be considered low on the player agency scale because they each fail to provide the points of agency of the other. Many systems blend some of these elements together (with varying degrees of success), but I find it hard to imagine a system that was high on both of them.