The ocean is meant to be a bit hilly underwater, maybe I'll make the hills smaller a bit. With river, I'll get rid of the hills altogether, or maybe only very slight ones. That's the kind of tweaking I had in mind
Of course it'll be a bit slower, it does quite a bit more calculations. Is it that much slower to you? I couldn't really compare, my computer is too fast, so the chunks/sec feature didn't fire up when I was comparing only the biome generation (i. e. using DebugBiomes composition and Flat height, I had over 500 ch/s and the reporting is not precise with such a huge number)
Maybe it's only perceived slowness, as this biome generator makes more forest and jungle biomes, thus having more trees, which are slower to generate.
I've adjusted the river height generator to have less hills. Now I noticed that even though we have a river biome, there is actually very little water generated in it, because it's too small. So it's time for you to go and try to find the best parameters to generate a nice terrain. I think enlarging MultiStepMapRiverWidth would help with the rivers. Maybe the biomes are too small, too, so enlarge MultiStepMapLandBiomeSize? It's up to you now