On a philosophical note:
It's kinda wonderful how far we've come with with continues functions to generate noise maps to generate terrain. It's amazing it looks like somewhat of a real landscape at all. It works so well, that now people are surprised there are things it just can't do. I think rivers fundamentally break with that concept. To get realistic rivers you have to iteratively simulate geology of a whole interconnected world instead generate the next chunk.
And as @jerjerje said any realistic river is always highly dependent on the neighboring terrain. It will make vastly distanced landmarks "dependent" on one another and break procedural generation.
I think when you zoom out on a vintage story map you can clearly see that it's just a noise map. I agree with the general trend of the discussion that Vintage story should make use of it's huge advantage of having a finite world where you can do some calculations globally when generating the world. There should be a large scale geology layer on the same level as the current climate/temperature map rather than doing all of it per chunk. To get more varied beautiful worlds.
