i do not believe rivers are getting enough love in rust. I dont think anyone playing the game can really say that they think the rivers look good, or add something important to the game other than suplying us with pumpkins and corn.
the rivers in the game are not very good at being rivers all of the time either. it gets a bit goofy were the river meets the ocean.
there is a posibility to get even more creative with rivers too, they could for example run into a lake og maybe even bandit camp on the mainland, instead of just ending in a random rock placed in the middle of nowhere.