I don't think the wider trade/economy got any work yet...
But since all dwarves in your fort are historical figures, and historical figures can migrate to your fort or visit it as traders/diplomats/with invasions, you can definitely affect the world. The killing of invaders and their animals would logically affect their site of origin's humanoid and animal populations, now that armies (IIRC not caravans though) are moving around on the map, instead of just spawning at your site.
Also, inheritance should work now, so after the king comes to your fort, if he dies, someone else will inherit the title, and the heir doesn't have to be in your fort.
And in general, retiring is a huge boon in this regard. You can spread the dwarven civilization. I've also had visions of neighbouring or probably slightly overlapping embarks that would build roads across continents. Effectively each "fort" would just be a roadside hamlet/watchpost on a 2x8 embark (same size as a 4x4). Maybe build a toll station. Or build a great wall. Or build/cast bridges/dig tunnels to allow crossing any straits/gulfs/lakes that are narrow enough. Ok, ok, you can do most of those now too, but being able to retire them and leave the dwarves living there instead of just abandoning makes it better. And world simulation continuing doing play and the new stuff to do in adventurer mode have me finally wanting to try that out. Once I've retired a few forts and built a bridge or two etc. in the world, that is.