Rivers and beaches are actually the domain of the biome generator. The height generator has nothing to do with it.
I don't think I'll be touching that in the nearest future, I'm more concerned about composition now. Deserts should get sand, swampland shouldn't have sand, etc.
And of the most impotance - we definitely need a biome generator cache, because the new height generator uses 9 chunks worth of biomes for each chunk generated, resulting in about 5 times slower chunk generation.
I don't think I'll be touching that in the nearest future, I'm more concerned about composition now. Deserts should get sand, swampland shouldn't have sand, etc.
And of the most impotance - we definitely need a biome generator cache, because the new height generator uses 9 chunks worth of biomes for each chunk generated, resulting in about 5 times slower chunk generation.