This is well stated, IMHO.
As I see it, option one is to make your characters players in the dog eat dog world of villainy/the underworld, or something like that. It would be much like the traditional adventure structure in that there are goals that your side has, or more likely, goals of someone else that you want to oppose, although the narrative, even plot may have a darker edge to it. You adversaries may be bad guys like you, worse guys, or the good guys. In opposing them, you distrupt their plans, maybe even destroy them, but you don't conquer the world. To run this style of adventure, you just need to have goals to oppose. "Conquering the world" isn't going to be the result of disrupting someone else's goal. It's going to be your goal. One that you need to push, which leads to option 2.
Option 2 is the we want to play Palpatine approach. We want to go out of our way to plot against someone, or everyone. When we're done, we will rule everything (incidentally, I think Palpatine's vendetta against the Jedi makes the story more interesting than if they are purely an obstacle he must eliminate on his path to conquest, that he otherwise wouldn't care about). We want to explore to see which new groups we can stumble across to take wealth and power from and/or use to our advantage somehow. We want to stay hidden, and plot and scheme. Success in this style of "adventure" is going to me more about avoiding discovery, avoiding combat (or killing all witnesses), and keeping tabs on how your plans are effecting your enemy. This group may introduce greater powers that you can ally with and that you then have to watch your back against (or deliver on promises to) - fiend lords, ancient undead, and whatnot. In either case, the game ends when you've conquered the world. I think the suggestion to pick up a setting book and try to undermine everyone in it and/or turn them against each other is a good way to approach this. You can start small, and serve one person's agenda to build skills and contacts, in which case, the game morphs into a combination of type 1 and type 2. This would need to be okay with you as a player though, that the game sometimes focuses on you executing someone else's agenda, and will later shift to one where each session focuses fully on your own agenda (assuming you make it that far). Or you can start big, and assume you're ready to do it all on your own from the beginning.
In thinking about this, I decided there's also an option 3. War. Start with a big enough army, and you're ready to launch your big invasion, or almost so. The camp[aign will be largely about one side winning, and the other losing. If you win, you're top dog. And if not, game over.